644975160 has 32 divisors (see below), whose sum is σ = 1934925840. Its totient is φ = 171993344.

The previous prime is 644975117. The next prime is 644975183. The reversal of 644975160 is 61579446.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 2687277 + ... + 2687516.

Almost surely, 2^644975160 is an apocalyptic number.

644975160 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644975160 is an abundant number, since it is smaller than the sum of its proper divisors (1289950680).

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

644975160 is a wasteful number, since it uses less digits than its factorization.

644975160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5374807 (or 5374803 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 42.

The square root of 644975160 is about 25396.3611566697. The cubic root of 644975160 is about 864.0011681226.

The spelling of 644975160 in words is "six hundred forty-four million, nine hundred seventy-five thousand, one hundred sixty".