# 169 (number)

 ← 168 169 170 →
Cardinal one hundred sixty-nine
Ordinal 169th
(one hundred sixty-ninth)
Factorization 132
Divisors 1, 13, 169
Greek numeral ΡΞΘ´
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 ${\displaystyle 8^{3}-7^{3}.}$