639024725840 has 20 divisors (see below), whose sum is σ = 1485732487764. Its totient is φ = 255609890304.

The previous prime is 639024725819. The next prime is 639024725881. The reversal of 639024725840 is 48527420936.

It can be written as a sum of positive squares in 2 ways, for example, as 481291837504 + 157732888336 = 693752^2 + 397156^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3993904457 + ... + 3993904616.

Almost surely, 2^639024725840 is an apocalyptic number.

It is an amenable number.

639024725840 is an abundant number, since it is smaller than the sum of its proper divisors (846707761924).

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

639024725840 is a wasteful number, since it uses less digits than its factorization.

639024725840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7987809086 (or 7987809080 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 50.

The spelling of 639024725840 in words is "six hundred thirty-nine billion, twenty-four million, seven hundred twenty-five thousand, eight hundred forty".