644331652 has 12 divisors (see below), whose sum is σ = 1163954176. Its totient is φ = 311773320.

The previous prime is 644331631. The next prime is 644331679. The reversal of 644331652 is 256133446.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

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, 2597988 + ... + 2598235.

Almost surely, 2^644331652 is an apocalyptic number.

644331652 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

644331652 is a deficient number, since it is larger than the sum of its proper divisors (519622524).

644331652 is a wasteful number, since it uses less digits than its factorization.

644331652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5196258 (or 5196256 counting only the distinct ones).

The product of its digits is 51840, while the sum is 34.

The square root of 644331652 is about 25383.6886996354. The cubic root of 644331652 is about 863.7137272464.

The spelling of 644331652 in words is "six hundred forty-four million, three hundred thirty-one thousand, six hundred fifty-two".