644332364615 has 16 divisors (see below), whose sum is σ = 776703386496. Its totient is φ = 513133920000.

The previous prime is 644332364581. The next prime is 644332364693. The reversal of 644332364615 is 516463233446.

It is not a de Polignac number, because 644332364615 - 2³² = 640037397319 is a prime.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644332364615.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 901205 + ... + 1449425.

It is an arithmetic number, because the mean of its divisors is an integer number (48543961656).

Almost surely, 2^644332364615 is an apocalyptic number.

644332364615 is a deficient number, since it is larger than the sum of its proper divisors (132371021881).

644332364615 is a wasteful number, since it uses less digits than its factorization.

644332364615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549290.

The product of its digits is 3732480, while the sum is 47.

The spelling of 644332364615 in words is "six hundred forty-four billion, three hundred thirty-two million, three hundred sixty-four thousand, six hundred fifteen".