165555665 has 16 divisors (see below), whose sum is σ = 218880576. Its totient is φ = 119208000.

The previous prime is 165555659. The next prime is 165555739. The reversal of 165555665 is 566555561.

It is not a de Polignac number, because 165555665 - 2⁶ = 165555601 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9347 + ... + 20456.

It is an arithmetic number, because the mean of its divisors is an integer number (13680036).

Almost surely, 2^165555665 is an apocalyptic number.

It is an amenable number.

165555665 is a deficient number, since it is larger than the sum of its proper divisors (53324911).

165555665 is a wasteful number, since it uses less digits than its factorization.

165555665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29920.

The product of its digits is 675000, while the sum is 44.

The square root of 165555665 is about 12866.8436300439. The cubic root of 165555665 is about 549.0956653827.

The spelling of 165555665 in words is "one hundred sixty-five million, five hundred fifty-five thousand, six hundred sixty-five".