644607516 has 48 divisors (see below), whose sum is σ = 1720244736. Its totient is φ = 184035264.

The previous prime is 644607511. The next prime is 644607517. The reversal of 644607516 is 615706446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644607511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 173470 + ... + 177146.

It is an arithmetic number, because the mean of its divisors is an integer number (35838432).

Almost surely, 2^644607516 is an apocalyptic number.

It is an amenable number.

644607516 is an abundant number, since it is smaller than the sum of its proper divisors (1075637220).

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

644607516 is a wasteful number, since it uses less digits than its factorization.

644607516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5778 (or 5776 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 39.

The square root of 644607516 is about 25389.1220013611. The cubic root of 644607516 is about 863.8369730558.

The spelling of 644607516 in words is "six hundred forty-four million, six hundred seven thousand, five hundred sixteen".