644376976 has 20 divisors (see below), whose sum is σ = 1321920972. Its totient is φ = 303236096.

The previous prime is 644376923. The next prime is 644376983. The reversal of 644376976 is 679673446.

It can be written as a sum of positive squares in 2 ways, for example, as 487526400 + 156850576 = 22080^2 + 12524^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1184245 + ... + 1184788.

Almost surely, 2^644376976 is an apocalyptic number.

It is an amenable number.

644376976 is an abundant number, since it is smaller than the sum of its proper divisors (677543996).

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

644376976 is a wasteful number, since it uses less digits than its factorization.

644376976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2369058 (or 2369052 counting only the distinct ones).

The product of its digits is 4572288, while the sum is 52.

The square root of 644376976 is about 25384.5814619820. The cubic root of 644376976 is about 863.7339787442.

The spelling of 644376976 in words is "six hundred forty-four million, three hundred seventy-six thousand, nine hundred seventy-six".