644316984 has 64 divisors (see below), whose sum is σ = 1827878400. Its totient is φ = 210199392.

The previous prime is 644316979. The next prime is 644317007. The reversal of 644316984 is 489613446.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21582 + ... + 41885.

It is an arithmetic number, because the mean of its divisors is an integer number (28560600).

Almost surely, 2^644316984 is an apocalyptic number.

It is an amenable number.

644316984 is an abundant number, since it is smaller than the sum of its proper divisors (1183561416).

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

644316984 is a wasteful number, since it uses less digits than its factorization.

644316984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63529 (or 63519 counting only the distinct ones).

The product of its digits is 497664, while the sum is 45.

The square root of 644316984 is about 25383.3997722921. The cubic root of 644316984 is about 863.7071731429.

The spelling of 644316984 in words is "six hundred forty-four million, three hundred sixteen thousand, nine hundred eighty-four".