165644720 has 20 divisors (see below), whose sum is σ = 385124160. Its totient is φ = 66257856.

The previous prime is 165644701. The next prime is 165644737. The reversal of 165644720 is 27446561.

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1035200 + ... + 1035359.

It is an arithmetic number, because the mean of its divisors is an integer number (19256208).

Almost surely, 2^165644720 is an apocalyptic number.

165644720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165644720 is an abundant number, since it is smaller than the sum of its proper divisors (219479440).

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

165644720 is a wasteful number, since it uses less digits than its factorization.

165644720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2070572 (or 2070566 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 165644720 is about 12870.3038037181. The cubic root of 165644720 is about 549.1941034702.

The spelling of 165644720 in words is "one hundred sixty-five million, six hundred forty-four thousand, seven hundred twenty".