169 (NUMBER)

''For the year AD, see 169 AD.''
'169' is the natural number following 168 and preceding 170.

169
Cardinal	one hundred [and] sixty-nine
Ordinal	169th
Factorization	$169\; =\; 13^2$
Roman numeral	CLXIX
Binary	10101001
Hexadecimal	A9

Being 13 squared, 169 is one of the few squares to also be a centered hexagonal number. But like any other odd square, it is a centered octagonal number.
It is an odd-indexed Pell number, thus it's also a Markov number, appearing in the solutions (2, 169, 985), (2, 29, 169), (29, 169, 14701), ...
It is the sum of seven consecutive primes, 13 + 17 + 19 + 23 + 29 + 31 + 37.
It is the number of nonequivalent starting hands in Texas hold 'em.
16.9 is the amount of fluid in most bottles of drinks.
169 is on the score board on the video game Guitar Hero along with the numbers 666.
169 is known in the computing world as the first number of an automatic IPv4 address assigned by TCP/IP when no external networking device is contactable.
13 squared, 13 being an unlucky number, is also 169.
See also one hundred sixty