165535865 has 12 divisors (see below), whose sum is σ = 218343972. Its totient is φ = 120389280.

The previous prime is 165535837. The next prime is 165535873. The reversal of 165535865 is 568535561.

It can be written as a sum of positive squares in 2 ways, for example, as 88868329 + 76667536 = 9427^2 + 8756^2 .

It is not a de Polignac number, because 165535865 - 2⁸ = 165535609 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 136202 + ... + 137411.

It is an arithmetic number, because the mean of its divisors is an integer number (18195331).

Almost surely, 2^165535865 is an apocalyptic number.

It is an amenable number.

165535865 is a deficient number, since it is larger than the sum of its proper divisors (52808107).

165535865 is a wasteful number, since it uses less digits than its factorization.

165535865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273640 (or 273629 counting only the distinct ones).

The product of its digits is 540000, while the sum is 44.

The square root of 165535865 is about 12866.0741875679. The cubic root of 165535865 is about 549.0737744019.

The spelling of 165535865 in words is "one hundred sixty-five million, five hundred thirty-five thousand, eight hundred sixty-five".