644874437787056 has 40 divisors (see below), whose sum is σ = 1298222465163120. Its totient is φ = 309947246061824.

The previous prime is 644874437786947. The next prime is 644874437787119. The reversal of 644874437787056 is 650787734478446.

It is a super-3 number, since 3×644874437787056³ (a number of 45 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3061162511 + ... + 3061373166.

It is an arithmetic number, because the mean of its divisors is an integer number (32455561629078).

Almost surely, 2^{644874437787056} is an apocalyptic number.

It is an amenable number.

644874437787056 is an abundant number, since it is smaller than the sum of its proper divisors (653348027376064).

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

644874437787056 is a wasteful number, since it uses less digits than its factorization.

644874437787056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6122535941 (or 6122535935 counting only the distinct ones).

The product of its (nonzero) digits is 21242511360, while the sum is 80.

The spelling of 644874437787056 in words is "six hundred forty-four trillion, eight hundred seventy-four billion, four hundred thirty-seven million, seven hundred eighty-seven thousand, fifty-six".