639476638880 has 96 divisors (see below), whose sum is σ = 1542832283664. Its totient is φ = 250383384576.

The previous prime is 639476638817. The next prime is 639476638897. The reversal of 639476638880 is 88836674936.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 116753422864 + 522723216016 = 341692^2 + 722996^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 639476638880.

It is an unprimeable number.

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, 3584762 + ... + 3758918.

Almost surely, 2^639476638880 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639476638880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (771416141832).

639476638880 is an abundant number, since it is smaller than the sum of its proper divisors (903355644784).

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

639476638880 is a wasteful number, since it uses less digits than its factorization.

639476638880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174658 (or 174650 counting only the distinct ones).

The product of its (nonzero) digits is 250822656, while the sum is 68.

The spelling of 639476638880 in words is "six hundred thirty-nine billion, four hundred seventy-six million, six hundred thirty-eight thousand, eight hundred eighty".