644315900 has 18 divisors (see below), whose sum is σ = 1398165720. Its totient is φ = 257726320.

The previous prime is 644315899. The next prime is 644315909. The reversal of 644315900 is 9513446.

644315900 = T₇₁₆₇ + T₇₁₆₈ + ... + T₇₁₉₁.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644315909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3221480 + ... + 3221679.

Almost surely, 2^644315900 is an apocalyptic number.

It is an amenable number.

644315900 is an abundant number, since it is smaller than the sum of its proper divisors (753849820).

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

644315900 is a wasteful number, since it uses less digits than its factorization.

644315900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6443173 (or 6443166 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 644315900 is about 25383.3784197455. The cubic root of 644315900 is about 863.7066887751.

The spelling of 644315900 in words is "six hundred forty-four million, three hundred fifteen thousand, nine hundred".