639388794672 has 60 divisors (see below), whose sum is σ = 1789897308784. Its totient is φ = 213070435200.

The previous prime is 639388794647. The next prime is 639388794683. The reversal of 639388794672 is 276497883936.

639388794672 is a `hidden beast` number, since 6 + 3 + 93 + 8 + 8 + 79 + 467 + 2 = 666.

It is a super-2 number, since 2×639388794672² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a self number, because there is not a number n which added to its sum of digits gives 639388794672.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94204 + ... + 1134747.

Almost surely, 2^639388794672 is an apocalyptic number.

It is an amenable number.

639388794672 is an abundant number, since it is smaller than the sum of its proper divisors (1150508514112).

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

639388794672 is a wasteful number, since it uses less digits than its factorization.

639388794672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1232578 (or 1232569 counting only the distinct ones).

The product of its digits is 658409472, while the sum is 72.

The spelling of 639388794672 in words is "six hundred thirty-nine billion, three hundred eighty-eight million, seven hundred ninety-four thousand, six hundred seventy-two".