165638400 has 108 divisors (see below), whose sum is σ = 546704592. Its totient is φ = 44165120.

The previous prime is 165638357. The next prime is 165638411. The reversal of 165638400 is 4836561.

165638400 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14887 + ... + 23513.

Almost surely, 2^165638400 is an apocalyptic number.

165638400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165638400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (273352296).

165638400 is an abundant number, since it is smaller than the sum of its proper divisors (381066192).

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

165638400 is an equidigital number, since it uses as much as digits as its factorization.

165638400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8656 (or 8637 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 165638400 is about 12870.0582749263. The cubic root of 165638400 is about 549.1871187403.

The spelling of 165638400 in words is "one hundred sixty-five million, six hundred thirty-eight thousand, four hundred".