644326056 has 64 divisors (see below), whose sum is σ = 1952510400. Its totient is φ = 195249600.

The previous prime is 644326051. The next prime is 644326057. The reversal of 644326056 is 650623446.

644326056 is a `hidden beast` number, since 6 + 4 + 43 + 2 + 605 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 644326056.

It is not an unprimeable number, because it can be changed into a prime (644326051) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 133215 + ... + 137966.

It is an arithmetic number, because the mean of its divisors is an integer number (30507975).

Almost surely, 2^644326056 is an apocalyptic number.

644326056 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

644326056 is an abundant number, since it is smaller than the sum of its proper divisors (1308184344).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644326056 is a wasteful number, since it uses less digits than its factorization.

644326056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271207 (or 271197 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 644326056 is about 25383.5784711297. The cubic root of 644326056 is about 863.7112267971.

The spelling of 644326056 in words is "six hundred forty-four million, three hundred twenty-six thousand, fifty-six".