165420864 has 126 divisors (see below), whose sum is σ = 551655234. Its totient is φ = 47255040.

The previous prime is 165420851. The next prime is 165420883. The reversal of 165420864 is 468024561.

It can be written as a sum of positive squares in only one way, i.e., 138297600 + 27123264 = 11760^2 + 5208^2 .

It is a tau number, because it is divible by the number of its divisors (126).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 25294 + ... + 31154.

Almost surely, 2^165420864 is an apocalyptic number.

165420864 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165420864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (275827617).

165420864 is an abundant number, since it is smaller than the sum of its proper divisors (386234370).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

165420864 is a wasteful number, since it uses less digits than its factorization.

165420864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5893 (or 5873 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 165420864 is about 12861.6042545244. The cubic root of 165420864 is about 548.9465941858.

The spelling of 165420864 in words is "one hundred sixty-five million, four hundred twenty thousand, eight hundred sixty-four".