169 (number)

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← 168 169 170 →
Cardinalone hundred sixty-nine
Ordinal169th
(one hundred sixty-ninth)
Factorization132
Divisors1, 13, 169
Greek numeralΡΞΘ´
Roman numeralCLXIX
Binary101010012
Ternary200213
Quaternary22214
Quinary11345
Senary4416
Octal2518
Duodecimal12112
HexadecimalA916
Vigesimal8920
Base 364P36

169 (one hundred [and] sixty-nine) is the natural number following 168 and preceding 170.

In mathematics[edit]

169 is an odd number, a composite number, and a deficient number.

169 is a square number: 13 x 13 = 169, and if each number is reversed the equation is still true: 31 x 31 = 961. 144 shares this property: 12 x 12 = 144, 21 x 21 = 441.

169 is one of the few squares to also be a centered hexagonal number.[1] Like all odd squares, it is a centered octagonal number. 169 is an odd-indexed Pell number, thus it is also a Markov number, appearing in the solutions (2, 169, 985), (2, 29, 169), (29, 169, 14701), etc. 169 is the sum of seven consecutive primes: 13 + 17 + 19 + 23 + 29 + 31 + 37. 169 is a difference in consecutive cubes, equaling

In astronomy[edit]

In geography[edit]

In the military[edit]

In transportation[edit]

In TV and radio[edit]

In other fields[edit]

169 is also:

See also[edit]

External links[edit]

References[edit]

  1. ^ "Sloane's A003215 : Hex (or centered hexagonal) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-28.