165665440 has 24 divisors (see below), whose sum is σ = 391384980. Its totient is φ = 66266112.

The previous prime is 165665431. The next prime is 165665441. The reversal of 165665440 is 44566561.

It can be written as a sum of positive squares in 2 ways, for example, as 155451024 + 10214416 = 12468^2 + 3196^2 .

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 165665440.

It is not an unprimeable number, because it can be changed into a prime (165665441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 517545 + ... + 517864.

Almost surely, 2^165665440 is an apocalyptic number.

165665440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165665440 is an abundant number, since it is smaller than the sum of its proper divisors (225719540).

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

165665440 is a wasteful number, since it uses less digits than its factorization.

165665440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1035424 (or 1035416 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 37.

The square root of 165665440 is about 12871.1087323509. The cubic root of 165665440 is about 549.2170015285.

The spelling of 165665440 in words is "one hundred sixty-five million, six hundred sixty-five thousand, four hundred forty".