20,000

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← 19999 20000 20001 →
Cardinaltwenty thousand
Ordinal20000th
(twenty thousandth)
Factorization25 × 54
Greek numeral
Roman numeralXX
Binary1001110001000002
Ternary10001022023
Quaternary103202004
Quinary11200005
Senary2323326
Octal470408
DuodecimalB6A812
Hexadecimal4E2016
Vigesimal2A0020
Base 36FFK36

20,000 (twenty thousand) is the natural number that comes after 19,999 and before 20,001.

20,000 is a round number, and is also in the title of Jules Verne's novel Twenty Thousand Leagues Under the Sea.

Selected numbers in the range 20001–29999[edit]

20001 to 20999[edit]

21000 to 21999[edit]

22000 to 22999[edit]

23000 to 23999[edit]

  • 23401 – Leyland number:[3] 65 + 56
  • 23409 – sum of the cubes of the first 17 positive integers
  • 23497 – cuban prime[9]
  • 23821 – square pyramidal number[4]
  • 23969 – octahedral number[7]
  • 23976 – pentagonal pyramidal number[2]

24000 to 24999[edit]

25000 to 25999[edit]

  • 25011 – the first composite number that in base 10 remains composite after any insertion of a digit
  • 25085 – Zeisel number[11]
  • 25117 – cuban prime[9]
  • 25200 – highly composite number[1]
  • 25205 – largest number whose factorial is less than 10100000
  • 25585 – square pyramidal number[4]

26000 to 26999[edit]

  • 26214 – octahedral number[7]
  • 26227 – cuban prime[9]
  • 26861 – smallest number below which there are more primes of the form 4k + 1 than of the form 4k + 3, against Chebyshev's bias
  • 26896 – 1642, palindromic in base 9: 408049

27000 to 27999[edit]

  • 27000 – 303
  • 27434 – square pyramidal number[4]
  • 27559 – Zeisel number[11]
  • 27648 – 11 × 22 × 33 × 44
  • 27720 – highly composite number;[1] smallest number divisible by the numbers 1 to 12 (there is no smaller number divisible by the numbers 1 to 11)
  • 27846harmonic divisor number[13]

28000 to 28999[edit]

29000 to 29999[edit]

  • 29241 – sum of the cubes of the first 18 positive integers
  • 29341Carmichael number[16]
  • 29370 – square pyramidal number[4]
  • 29791 – 313

References[edit]

  1. ^ a b c "Sloane's A002182 : Highly composite numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  2. ^ a b c d "Sloane's A002411 : Pentagonal pyramidal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  3. ^ a b "Sloane's A076980 : Leyland numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  4. ^ a b c d e f "Sloane's A000330 : Square pyramidal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  5. ^ "Sloane's A000078 : Tetranacci numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  6. ^ "Sloane's A000110 : Bell or exponential numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  7. ^ a b c d "Sloane's A005900 : Octahedral numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  8. ^ "Sloane's A006886 : Kaprekar numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  9. ^ a b c d e "Sloane's A002407 : Cuban primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  10. ^ "Sloane's A003261 : Woodall numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  11. ^ a b c "Sloane's A051015 : Zeisel numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  12. ^ "Sloane's A001190 : Wedderburn-Etherington numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  13. ^ "Sloane's A001599 : Harmonic or Ore numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  14. ^ "Sloane's A000045 : Fibonacci numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  15. ^ "Sloane's A002559 : Markoff (or Markov) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.
  16. ^ "Sloane's A002997 : Carmichael numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-15.