644272400 has 30 divisors (see below), whose sum is σ = 1547865402. Its totient is φ = 257708800.

The previous prime is 644272393. The next prime is 644272427. The reversal of 644272400 is 4272446.

It can be written as a sum of positive squares in 3 ways, for example, as 157452304 + 486820096 = 12548^2 + 22064^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 804941 + ... + 805740.

Almost surely, 2^644272400 is an apocalyptic number.

It is an amenable number.

644272400 is an abundant number, since it is smaller than the sum of its proper divisors (903593002).

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

644272400 is a wasteful number, since it uses less digits than its factorization.

644272400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1610699 (or 1610688 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 29.

The square root of 644272400 is about 25382.5215453469. The cubic root of 644272400 is about 863.6872510601.

The spelling of 644272400 in words is "six hundred forty-four million, two hundred seventy-two thousand, four hundred".