165640500 has 72 divisors (see below), whose sum is σ = 522554760. Its totient is φ = 44169600.

The previous prime is 165640487. The next prime is 165640511. The reversal of 165640500 is 5046561.

It is a happy number.

165640500 is a `hidden beast` number, since 1 + 656 + 4 + 0 + 5 + 0 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 12574116 + 153066384 = 3546^2 + 12372^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13905 + ... + 22904.

It is an arithmetic number, because the mean of its divisors is an integer number (7257705).

Almost surely, 2^165640500 is an apocalyptic number.

165640500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165640500 is an abundant number, since it is smaller than the sum of its proper divisors (356914260).

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

165640500 is a wasteful number, since it uses less digits than its factorization.

165640500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36834 (or 36819 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 165640500 is about 12870.1398593799. The cubic root of 165640500 is about 549.1894396355.

Subtracting from 165640500 its product of nonzero digits (3600), we obtain a square (165636900 = 12870²).

The spelling of 165640500 in words is "one hundred sixty-five million, six hundred forty thousand, five hundred".