# 1000 (number)

 ← 999 1000 1001 →
Cardinal one thousand
Ordinal 1000th
(one thousandth)
Factorization 23· 53
Divisors 1, 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 125, 200, 250, 500, 1000
Roman numeral M
Greek prefix chilia
Latin prefix milli
Binary 11111010002
Ternary 11010013
Quaternary 332204
Quinary 130005
Senary 43446
Octal 17508
Duodecimal 6B412
Vigesimal 2A020
Base 36 RS36
Tamil

1000 or 1,000 (one thousand) is the natural number following 999 and preceding 1001.

## In mathematics

• The decimal representation for one thousand is
• The SI prefix for a thousand is kilo-, officially abbreviated as k—for instance, prefixed to "metre" or its abbreviation m, kilometre or km signifies a thousand metres. As such, technically oriented people occasionally represent the number in a non-standard notation by replacing the last three zeros of the general numeral with "k": for instance, 30k for 30,000.
• By the SI writing style, a comma or a space can be used to as a thousands separator, i.e., to separate the digits of a number every power of 1000.
• The sum of Euler's totient function over the first 57 integers is 1000.
• Prime Curios! mentions that 1000 is the smallest number that generates three primes in the fastest way possible by concatenation of decremented numbers (1000999, 1000999998997, and 1000999998997996995994993 are prime). The criterion excludes counting the number itself.
• 1000 is a Harshad number in base 10.

## In popular culture

• A grand is a slang term for one thousand units of a given currency. Several grand can be shortened to Gs.
• The symbol K is sometimes used for a thousand, for example in referring to units of salary or in reference to the Y2K computer bug.
• Especially in the United States, the gambling community often refers to denominations of \$1000 as dimes.
• A picture is worth a thousand words.
• According to an ancient Japanese legend, anyone who folds a thousand origami cranes will be granted a wish by a crane.

## Selected numbers in the thousands (1001–1999)

### 1001–1249

1001sphenic number (7 × 11 × 13), pentagonal number, pentatope number
1002 – sphenic number, Mertens function zero, abundant number
1005 – Mertens function zero
1008 – divisible by the number of primes below it
1009 – first prime above 1000
1010 – Mertens function zero
1013 – Sophie Germain prime, centered square number, Mertens function zero
1014 – Mertens function zero
1015 – square pyramidal number
1016 – member of the Mian–Chowla sequence
1018 – Mertens function zero
1019 – Sophie Germain prime, safe prime
1020 – polydivisible number
1023 – the highest number one can count to on one's fingers using binary; also the magic number used in Global Positioning System signals
1024$2^{10}$, the number of bytes in a kilobyte (in 1999, the IEC coined kibibyte to use for 1024 with kilobyte being 1000, but this convention has not been widely adopted)
1027 – sum of the squares of the first eight primes; can be written from base 2 to base 18 using only the digits 0 to 9.
1028 – sum of totient function for first 58 integers; can be written from base 2 to base 18 using only the digits 0 to 9.
1029 – can be written from base 2 to base 18 using only the digits 0 to 9.
1031 – Sophie Germain prime
1033 – locale ID of English (United States) in (some version of) Windows.(VS.80).aspx.
1035 – triangular number, hexagonal number
1049 – Sophie Germain prime, highly cototient number
1051 – centered pentagonal number
1056 – pronic number
1060 – sum of the first 25 primes
1071 – heptagonal number
1072 – centered heptagonal number
1079 – every positive integer is the sum of at most 1079 tenth powers.
1080 – pentagonal number
1081 – triangular number, member of Padovan sequence
1086 – Smith number, sum of totient function for first 59 integers
1087 – Chen prime, cousin prime, lucky prime, Kynea number
1089$33^2$, nonagonal number, centered octagonal number
1091 – cousin prime and twin prime
1092 – divisible by the number of primes below it
1093 – the smallest Wieferich prime (the only other known Wieferich prime is 3511[1]), twin prime and star number
1102 – sum of totient function for first 60 integers
1103 – Sophie Germain prime, balanced prime
1104 – Keith number
1105 – Carmichael number, magic constant of n × n normal magic square and n-queens problem for n = 13, decagonal number, centered square number, 1105 = 332 + 42 = 322 + 92 = 312 + 122 = 232 + 242
1116 – divisible by the number of primes below it
1122 – pronic number, divisible by the number of primes below it
1123 – balanced prime
1124 – Leyland number
1128 – triangular number, hexagonal number, divisible by the number of primes below it
1134 - divisible by the number of primes below it
1138 – recurring number in the works of George Lucas and his companies, beginning with his first feature film – THX 1138; particularly, a special code for Easter eggs on Star Wars DVDs.
1140 – tetrahedral number
1152 – highly totient number
1153 – Proth prime
1156 – $34^2$, octahedral number, centered pentagonal number
1159 – member of the Mian–Chowla sequence
1161 – sum of the first 26 primes
1162 – pentagonal number, sum of totient function for first 61 integers
1169 – highly cototient number
1170 – highest possible score in a National Academic Quiz Tournaments (NAQT) match
1176 – triangular number
1177 – heptagonal number
1184 – amicable number with 1210[2]
1187 – safe prime, Stern prime, balanced prime
1190 – pronic number
1192 – sum of totient function for first 62 integers
1198 – centered heptagonal number
1200 – the number of households the Nielsen ratings sample[3]
1201 – centered square number
1210 – amicable number with 1184[4]
1216 – nonagonal number
1217 – Proth prime
1219 – Mertens function zero
1220 – Mertens function zero
1223 – Sophie Germain prime, balanced prime
1225 – $35^2$, triangular number, square triangular number, hexagonal number, centered octagonal number
1228 – sum of totient function for first 63 integers
1229 – Sophie Germain prime, number of primes between 0 and 10000
1233 – $12^2 + 33^2$
1240 – square pyramidal number
1241 – centered cube number
1242 – decagonal number
1247 – pentagonal number
1249 – emirp, trimorphic number

### 1250–1499

1255 – Mertens function zero
1256 – Mertens function zero
1258 – Mertens function zero
1259 – highly cototient number
1260 – highly composite number, pronic number, the smallest vampire number, sum of totient function for first 64 integers, this number appears twice in the Book of Revelation
1261 – star number, Mertens function zero
1264 – sum of the first 27 primes
1266 – centered pentagonal number, Mertens function zero
1270 – Mertens function zero
1275 – triangular number, sum of the first 50 natural numbers
1279 – Mertens function zero
1280 – Mertens function zero
1282 – Mertens function zero
1283 – safe prime
1285 – Mertens function zero
1288 – heptagonal number
1289 – Sophie Germain prime, Mertens function zero
1291 – Mertens function zero
1292 – Mertens function zero
1296 – 64, 362, sum of the cubes of the first eight positive integers, the number of rectangles on a normal 8 × 8 chessboard
1297 – Mertens function zero
1299 – Mertens function zero
1300 – Sum of the first 4 fifth powers, mertens function zero, largest possible win margin in an NAQT match
1301 – centered square number
1302 – Mertens function zero
1306 – Mertens function zero
1307 – safe prime
1308 – sum of totient function for first 65 integers
1309 – the first sphenic number followed by two consecutive such number
1312 – member of the Mian–Chowla sequence
1318 – Mertens function zero
1319 – safe prime
1325 – Markov number
1326 – triangular number, hexagonal number, Mertens function zero
1327 – first prime followed by 32 consecutive composite numbers
1328 – sum of totient function for first 66 integers
1329 – Mertens function zero
1330 – tetrahedral number, forms a Ruth–Aaron pair with 1331 under second definition
1331 – 113, centered heptagonal number, forms a Ruth–Aaron pair with 1330 under second definition. This is the only cube of the form x2+x-1, for x=36.
1332 – pronic number
1335 – pentagonal number, Mertens function zero
1336 – Mertens function zero
1337 – Used in the novel form of spelling called leet
1338 – Mertens function zero
1342 – Mertens function zero
1350 – nonagonal number
1365 – pentatope number
1367 – safe prime, balanced prime
1369 – 372, centered octagonal number
1371 – sum of the first 28 primes
1378 – triangular number
1379 – magic constant of n × n normal magic square and n-queens problem for n = 14.
1381 – centered pentagonal number
1387 – 5th Fermat pseudoprime of base 2, 22nd centered hexagonal number and the 19th decagonal number, second Super-Poulet number.
1394 – sum of totient function for first 67 integers
1395 – vampire number, member of the Mian–Chowla sequence
1404 – heptagonal number
1405 – $26^2 + 27^2$, $7^2 + 8^2 + \cdots + 16^2$, centered square number
1406 – pronic number, semi-meandric number
1409 – Sophie Germain prime, smallest number whose eighth power is the sum of 8 eighth powers, Proth prime
1419 – Zeisel number
1425 – self-descriptive number in base 5
1426 – sum of totient function for first 68 integers
1426 – pentagonal number
1430 – Catalan number
1431 – triangular number, hexagonal number
1432 – member of Padovan sequence
1433 - Typical port used for remote connections to Microsoft SQL Server databases
1435 – vampire number; the standard railway gauge in millimetres, equivalent to 4' 8½"
1439 – Sophie Germain prime, safe prime
1440 – a highly totient number and a 481-gonal number. Also, the number of minutes in one day, the blocksize of a standard 3.5" floppy disk, and the horizontal resolution of WXGA(II) computer displays
1441 – star number
1444 – $38^2$, smallest pandigital number in Roman numerals
1451 – Sophie Germain prime
1469 – octahedral number, highly cototient number
1470 – pentagonal pyramidal number, sum of totient function for first 69 integers
1471 – centered heptagonal number
1480 – sum of the first 29 primes
1481 – Sophie Germain prime
1482 – pronic number
1485 – triangular number
1487 – safe prime
1490 – tetranacci number
1491 – nonagonal number, Mertens function zero
1492 – Mertens function zero
1493 – Stern prime
1494 – sum of totient function for first 70 integers
1496 – square pyramidal number
1499 – Sophie Germain prime

### 1500–1749

1501 – centered pentagonal number
1511 – Sophie Germain prime, balanced prime
1513 – centered square number
1518 – Mertens function zero
1519 – Mertens function zero
1520 – pentagonal number, Mertens function zero, forms a Ruth–Aaron pair with 1521 under second definition
1521 – $39^2$, Mertens function zero, centered octagonal number, forms a Ruth–Aaron pair with 1520 under second definition
1523 – Mertens function zero, safe prime, member of the Mian–Chowla sequence
1524 – Mertens function zero
1525 – heptagonal number, Mertens function zero
1527 – Mertens function zero
1528 – Mertens function zero
1530 – vampire number
1531 – Mertens function zero
1532 – Mertens function zero
1535 – Thabit number
1537 – Keith number, Mertens function zero
1540 – triangular number, hexagonal number, decagonal number, tetrahedral number
1543 – Mertens function zero
1544 – Mertens function zero
1546 – Mertens function zero
1556 – sum of the squares of the first nine primes
1559 – Sophie Germain prime
1560 – pronic number
1564 – sum of totient function for first 71 integers
1572 – member of the Mian–Chowla sequence
1575 – odd abundant number
1583 – Sophie Germain prime
1588 – sum of totient function for first 72 integers
1593 – sum of the first 30 primes
1596 – triangular number
1597 – Fibonacci number, Markov number, Prime number, emirp
1600 – $40^2$, street number on Pennsylvania Avenue of the White House, Meters; Common High School Track Event, perfect score on SAT
1601 – Sophie Germain prime, Proth prime, the novel 1601 (Mark Twain)
1617 – pentagonal number
1618 – centered heptagonal number
1619 – safe prime
1625 – centered square number
1626 – centered pentagonal number
1633 – star number
1638 – harmonic divisor number
1639 – nonagonal number
1640 – pronic number
1649 – highly cototient number, Leyland number
1651 – heptagonal number
1653 – triangular number, hexagonal number
1657 – cuban prime
1660 – sum of totient function for first 73 integers
1666 – largest efficient pandigital number in Roman numerals (each symbol occurs exactly once)
1679 – highly cototient number, semiprime (23 × 73, see also Arecibo message)
1680 – highly composite number
1681 – $41^2$, smallest number yielded by the formula $n^2 + n + 41$ that is not a prime; centered octagonal number
1682 – member of a Ruth–Aaron pair (first definition)
1683 – member of a Ruth–Aaron pair (first definition)
1695 – magic constant of n × n normal magic square and n-queens problem for n = 15.
1696 – sum of totient function for first 74 integers
1701 – decagonal number, hull number of the U.S.S. Enterprise on Star Trek
1705 – tribonacci number
1709 – first of a sequence of eight primes formed by adding 57 in the middle. 1709, 175709, 17575709, 1757575709, 175757575709, 17575757575709, 1757575757575709 and 175757575757575709 are all prime, but 17575757575757575709 = 232433 × 75616446785773
1711 – triangular number
1717 – pentagonal number
1720 – sum of the first 31 primes
1722 – Giuga number, pronic number
1728 – the quantity expressed as 1000 in duodecimal, that is, the cube of twelve (called a great gross), and so, the number of cubic inches in a cubic foot
1729taxicab number, Carmichael number, Zeisel number, centered cube number, Hardy–Ramanujan number. In the decimal expansion of e the first time all 10 digits appear in sequence starts at the 1729th decimal place. In 1979 the rock musical Hair closed on Broadway in New York City after 1729 performances.
1733 – Sophie Germain prime
1736 – sum of totient function for first 75 integers
1741 – centered square number
1747 – balanced prime

### 1750–1999

1753 – balanced prime
1756 – centered pentagonal number
1764 – $42^2$
1770 – triangular number, hexagonal number, Town of Seventeen Seventy in Australia
1771 – tetrahedral number
1772 – centered heptagonal number, sum of totient function for first 76 integers
1782 – heptagonal number
1785 – square pyramidal number
1791 – largest natural number that cannot be expressed as a sum of at most four hexagonal numbers.
1794 – nonagonal number
1800 – pentagonal pyramidal number, also, in da Ponte's Don Giovanni, the number of women Don Giovanni had slept with so far when confronted by Donna Elvira, according to Leporello's tally
1801 – cuban prime
1806 – pronic number, product of first four terms of Sylvester's sequence, primary pseudoperfect number
1807 – fifth term of Sylvester's sequence
1811 – Sophie Germain prime
1820 – pentagonal number, pentatope number
1821 – member of the Mian–Chowla sequence
1823 – safe prime
1827 – vampire number
1828 – meandric number, open meandric number
1830 – triangular number
1832 – sum of totient function for first 77 integers
1834 – octahedral number, sum of the cubes of the first five primes
1836 – factor by which a proton is more massive than an electron
1837 – star number
1841 – Mertens function zero
1843 – Mertens function zero
1844 – Mertens function zero
1845 – Mertens function zero
1849 – $43^2$, centered octagonal number
1851 – sum of the first 32 primes
1853 – Mertens function zero
1854 – Mertens function zero
1856 – sum of totient function for first 78 integers
1857 – Mertens function zero
1861 – centered square number, Mertens function zero
1862 – Mertens function zero, forms a Ruth–Aaron pair with 1863 under second definition
1863 – Mertens function zero, forms a Ruth–Aaron pair with 1862 under second definition
1864 – Mertens function zero
1866 – Mertens function zero
1870 – decagonal number
1885 – Zeisel number
1889 – Sophie Germain prime, highly cototient number
1891 – triangular number, hexagonal number, centered pentagonal number
1892 – pronic number
1896 – member of the Mian–Chowla sequence
1897 – member of Padovan sequence
1900 – 1900 (film) or Novecento, 1977 movie
1901 – Sophie Germain prime
1907 – safe prime, balanced prime
1909 – hyperperfect number
1918 – heptagonal number
1926 – pentagonal number
1929 – Mertens function zero
1931 – Sophie Germain prime
1933 – centered heptagonal number, prime number
1934 – sum of totient function for first 79 integers
1936 – $44^2$
1938 – Mertens function zero
1951 – cuban prime, prime followed by a prime gap of 22.
1953 – triangular number
1956 – nonagonal number
1966 – sum of totient function for first 80 integers
1973 – Sophie Germain prime
1979 – prime number
1980 – pronic number