644255204 has 6 divisors (see below), whose sum is σ = 1127446614. Its totient is φ = 322127600.

The previous prime is 644255203. The next prime is 644255243. The reversal of 644255204 is 402552446.

644255204 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 350064100 + 294191104 = 18710^2 + 17152^2 .

It is not an unprimeable number, because it can be changed into a prime (644255203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80531897 + ... + 80531904.

It is an arithmetic number, because the mean of its divisors is an integer number (187907769).

Almost surely, 2^644255204 is an apocalyptic number.

It is an amenable number.

644255204 is a deficient number, since it is larger than the sum of its proper divisors (483191410).

644255204 is a wasteful number, since it uses less digits than its factorization.

644255204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161063805 (or 161063803 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 32.

The square root of 644255204 is about 25382.1828060551. The cubic root of 644255204 is about 863.6795668890.

The spelling of 644255204 in words is "six hundred forty-four million, two hundred fifty-five thousand, two hundred four".