# 169 (number)

 ← 168 169 170 →
Cardinal one hundred sixty-nine
Ordinal 169th
(one hundred sixty-ninth)
Factorization 132
Divisors 1, 13, 169
Roman numeral CLXIX
Binary 101010012
Ternary 200213
Quaternary 22214
Quinary 11345
Senary 4416
Octal 2518
Duodecimal 12112
Vigesimal 8920
Base 36 4P36

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

## In mathematics

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 ${\displaystyle 8^{3}-7^{3}.}$