644466824 has 16 divisors (see below), whose sum is σ = 1210553100. Its totient is φ = 321652672.

The previous prime is 644466811. The next prime is 644466841. The reversal of 644466824 is 428664446.

It can be written as a sum of positive squares in 2 ways, for example, as 644245924 + 220900 = 25382^2 + 470^2 .

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, 67859 + ... + 76770.

Almost surely, 2^644466824 is an apocalyptic number.

It is an amenable number.

644466824 is a deficient number, since it is larger than the sum of its proper divisors (566086276).

644466824 is a wasteful number, since it uses less digits than its factorization.

644466824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145192 (or 145188 counting only the distinct ones).

The product of its digits is 884736, while the sum is 44.

The square root of 644466824 is about 25386.3511359943. The cubic root of 644466824 is about 863.7741214799.

The spelling of 644466824 in words is "six hundred forty-four million, four hundred sixty-six thousand, eight hundred twenty-four".