644122264 has 16 divisors (see below), whose sum is σ = 1208535120. Its totient is φ = 321846240.

The previous prime is 644122207. The next prime is 644122273. The reversal of 644122264 is 462221446.

It is a happy number.

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, 13747 + ... + 38434.

It is an arithmetic number, because the mean of its divisors is an integer number (75533445).

Almost surely, 2^644122264 is an apocalyptic number.

It is an amenable number.

644122264 is a deficient number, since it is larger than the sum of its proper divisors (564412856).

644122264 is a wasteful number, since it uses less digits than its factorization.

644122264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53730 (or 53726 counting only the distinct ones).

The product of its digits is 18432, while the sum is 31.

The square root of 644122264 is about 25379.5639048428. The cubic root of 644122264 is about 863.6201569641.

The spelling of 644122264 in words is "six hundred forty-four million, one hundred twenty-two thousand, two hundred sixty-four".