644251072 has 28 divisors (see below), whose sum is σ = 1285600680. Its totient is φ = 320320256.

The previous prime is 644251051. The next prime is 644251087. The reversal of 644251072 is 270152446.

644251072 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

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, 16663 + ... + 39574.

It is an arithmetic number, because the mean of its divisors is an integer number (45914310).

Almost surely, 2^644251072 is an apocalyptic number.

It is an amenable number.

644251072 is a deficient number, since it is larger than the sum of its proper divisors (641349608).

644251072 is a wasteful number, since it uses less digits than its factorization.

644251072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56428 (or 56418 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 31.

The square root of 644251072 is about 25382.1014102458. The cubic root of 644251072 is about 863.6777204512.

The spelling of 644251072 in words is "six hundred forty-four million, two hundred fifty-one thousand, seventy-two".