644604464 has 40 divisors (see below), whose sum is σ = 1428554400. Its totient is φ = 276023808.

The previous prime is 644604461. The next prime is 644604473. The reversal of 644604464 is 464406446.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (644604461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 216812 + ... + 219764.

It is an arithmetic number, because the mean of its divisors is an integer number (35713860).

Almost surely, 2^644604464 is an apocalyptic number.

It is an amenable number.

644604464 is an abundant number, since it is smaller than the sum of its proper divisors (783949936).

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

644604464 is a wasteful number, since it uses less digits than its factorization.

644604464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4917 (or 4911 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 38.

The square root of 644604464 is about 25389.0618968090. The cubic root of 644604464 is about 863.8356097277.

The spelling of 644604464 in words is "six hundred forty-four million, six hundred four thousand, four hundred sixty-four".