644311264 has 24 divisors (see below), whose sum is σ = 1270185840. Its totient is φ = 321724416.

The previous prime is 644311253. The next prime is 644311267. The reversal of 644311264 is 462113446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644311267) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11517 + ... + 37699.

It is an arithmetic number, because the mean of its divisors is an integer number (52924410).

Almost surely, 2^644311264 is an apocalyptic number.

It is an amenable number.

644311264 is a deficient number, since it is larger than the sum of its proper divisors (625874576).

644311264 is a wasteful number, since it uses less digits than its factorization.

644311264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26962 (or 26954 counting only the distinct ones).

The product of its digits is 13824, while the sum is 31.

The square root of 644311264 is about 25383.2870999798. The cubic root of 644311264 is about 863.7046172479.

The spelling of 644311264 in words is "six hundred forty-four million, three hundred eleven thousand, two hundred sixty-four".