644484480 has 64 divisors (see below), whose sum is σ = 2054300400. Its totient is φ = 171862016.

The previous prime is 644484479. The next prime is 644484497. The reversal of 644484480 is 84484446.

It is a tau number, because it is divible by the number of its divisors (64).

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165915 + ... + 169754.

Almost surely, 2^644484480 is an apocalyptic number.

644484480 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644484480 is an abundant number, since it is smaller than the sum of its proper divisors (1409815920).

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

644484480 is a wasteful number, since it uses less digits than its factorization.

644484480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335691 (or 335679 counting only the distinct ones).

The product of its (nonzero) digits is 393216, while the sum is 42.

The square root of 644484480 is about 25386.6988795314. The cubic root of 644484480 is about 863.7820094767.

The spelling of 644484480 in words is "six hundred forty-four million, four hundred eighty-four thousand, four hundred eighty".