• 165 can be written using four 4's:
165 is nontrivially palindromic in base 2 and base 14.
165 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a sphenic number, since it is the product of 3 distinct primes.
165 is an idoneal number.
It is an alternating number because its digits alternate between odd and even.
It is a Curzon number.
165 is a nontrivial repdigit in base 14.
It is a plaindrome in base 8, base 12 and base 14.
It is a nialpdrome in base 4, base 6, base 13, base 14, base 15 and base 16.
It is a zygodrome in base 4 and base 14.
It is a self number, because there is not a number n which added to its sum of digits gives 165.
It is a congruent number.
It is the 9-th tetrahedral number.
165 is a gapful number since it is divisible by the number (15) formed by its first and last digit.
It is an amenable number.
165 is a wasteful number, since it uses less digits than its factorization.
165 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 19.
The square root of 165 is about 12.8452325787. The cubic root of 165 is about 5.4848065524.
Subtracting from 165 its sum of digits (12), we obtain a triangular number (153 = T17).
Multiplying 165 by its product of digits (30), we get a triangular number (4950 = T99).
The spelling of 165 in words is "one hundred sixty-five", and thus it is an aban number.