644351364 has 36 divisors (see below), whose sum is σ = 1636101376. Its totient is φ = 213817968.

The previous prime is 644351317. The next prime is 644351401. The reversal of 644351364 is 463153446.

644351364 is a `hidden beast` number, since 644 + 3 + 5 + 1 + 3 + 6 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32104 + ... + 48159.

Almost surely, 2^644351364 is an apocalyptic number.

It is an amenable number.

644351364 is an abundant number, since it is smaller than the sum of its proper divisors (991750012).

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

644351364 is a wasteful number, since it uses less digits than its factorization.

644351364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80496 (or 80491 counting only the distinct ones).

The product of its digits is 103680, while the sum is 36.

The square root of 644351364 is about 25384.0769775070. The cubic root of 644351364 is about 863.7225350042.

The spelling of 644351364 in words is "six hundred forty-four million, three hundred fifty-one thousand, three hundred sixty-four".