165915864 has 80 divisors (see below), whose sum is σ = 473584320. Its totient is φ = 54250560.

The previous prime is 165915857. The next prime is 165915877. The reversal of 165915864 is 468519561.

165915864 is a `hidden beast` number, since 1 + 6 + 591 + 58 + 6 + 4 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 31929 + ... + 36759.

It is an arithmetic number, because the mean of its divisors is an integer number (5919804).

Almost surely, 2^165915864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165915864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (236792160).

165915864 is an abundant number, since it is smaller than the sum of its proper divisors (307668456).

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

165915864 is a wasteful number, since it uses less digits than its factorization.

165915864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4902 (or 4889 counting only the distinct ones).

The product of its digits is 259200, while the sum is 45.

The square root of 165915864 is about 12880.8332028639. The cubic root of 165915864 is about 549.4935988986.

The spelling of 165915864 in words is "one hundred sixty-five million, nine hundred fifteen thousand, eight hundred sixty-four".