• 169 can be written using four 4's:
The square root of 169 is 13.
169 is nontrivially palindromic in base 12.
169 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
169 is an esthetic number in base 12 and base 16, because in such bases its adjacent digits differ by 1.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 961 = 312.
It is an alternating number because its digits alternate between odd and even.
It is a Duffinian number.
169 is an undulating number in base 12.
169 is a lucky number.
It is a plaindrome in base 5, base 10 and base 11.
It is a nialpdrome in base 4, base 6, base 7, base 13, base 14, base 15 and base 16.
It is a panconsummate number.
169 is the 13-th square number.
It is an amenable number.
169 is an equidigital number, since it uses as much as digits as its factorization.
169 is an evil number, because the sum of its binary digits is even.
The cubic root of 169 is about 5.5287748137.
Subtracting from 169 its sum of digits (16), we obtain a triangular number (153 = T17).
Multiplying 169 by its sum of digits (16), we get a square (2704 = 522).
Multiplying 169 by its reverse (961), we get a square (162409 = 4032).
The spelling of 169 in words is "one hundred sixty-nine", and thus it is an aban number.