644592160 has 96 divisors (see below), whose sum is σ = 1577629872. Its totient is φ = 248709120.

The previous prime is 644592107. The next prime is 644592163. The reversal of 644592160 is 61295446.

It can be written as a sum of positive squares in 8 ways, for example, as 853776 + 643738384 = 924^2 + 25372^2 .

It is not an unprimeable number, because it can be changed into a prime (644592163) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 635814 + ... + 636826.

Almost surely, 2^644592160 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644592160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (788814936).

644592160 is an abundant number, since it is smaller than the sum of its proper divisors (933037712).

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

644592160 is a wasteful number, since it uses less digits than its factorization.

644592160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1166 (or 1158 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 644592160 is about 25388.8195865818. The cubic root of 644592160 is about 863.8301134885.

The spelling of 644592160 in words is "six hundred forty-four million, five hundred ninety-two thousand, one hundred sixty".