639424431522 has 54 divisors (see below), whose sum is σ = 1420343459379. Its totient is φ = 207897670080.

The previous prime is 639424431463. The next prime is 639424431557. The reversal of 639424431522 is 225134424936.

639424431522 is a `hidden beast` number, since 6 + 3 + 94 + 2 + 4 + 4 + 31 + 522 = 666.

It can be written as a sum of positive squares in 5 ways, for example, as 53019207081 + 586405224441 = 230259^2 + 765771^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=565431.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 139093728 + ... + 139098324.

Almost surely, 2^639424431522 is an apocalyptic number.

639424431522 is an abundant number, since it is smaller than the sum of its proper divisors (780919027857).

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

639424431522 is an frugal number, since it uses more digits than its factorization.

639424431522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9284 (or 4643 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 45.

The spelling of 639424431522 in words is "six hundred thirty-nine billion, four hundred twenty-four million, four hundred thirty-one thousand, five hundred twenty-two".