639642947064 has 64 divisors (see below), whose sum is σ = 1744551648000. Its totient is φ = 193823320320.

The previous prime is 639642947059. The next prime is 639642947071. The reversal of 639642947064 is 460749246936.

It is a junction number, because it is equal to n+sod(n) for n = 639642946989 and 639642947007.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12881917 + ... + 12931475.

It is an arithmetic number, because the mean of its divisors is an integer number (27258619500).

Almost surely, 2^639642947064 is an apocalyptic number.

It is an amenable number.

639642947064 is an abundant number, since it is smaller than the sum of its proper divisors (1104908700936).

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

639642947064 is a wasteful number, since it uses less digits than its factorization.

639642947064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98468 (or 98464 counting only the distinct ones).

The product of its (nonzero) digits is 47029248, while the sum is 60.

The spelling of 639642947064 in words is "six hundred thirty-nine billion, six hundred forty-two million, nine hundred forty-seven thousand, sixty-four".