639393945764 has 36 divisors (see below), whose sum is σ = 1307069608320. Its totient is φ = 272879404560.

The previous prime is 639393945737. The next prime is 639393945769. The reversal of 639393945764 is 467549393936.

639393945764 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 639393945694 and 639393945703.

It is not an unprimeable number, because it can be changed into a prime (639393945769) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6777872 + ... + 6871559.

It is an arithmetic number, because the mean of its divisors is an integer number (36307489120).

Almost surely, 2^639393945764 is an apocalyptic number.

It is an amenable number.

639393945764 is an abundant number, since it is smaller than the sum of its proper divisors (667675662556).

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

639393945764 is a wasteful number, since it uses less digits than its factorization.

639393945764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13649688 (or 13649679 counting only the distinct ones).

The product of its digits is 396809280, while the sum is 68.

The spelling of 639393945764 in words is "six hundred thirty-nine billion, three hundred ninety-three million, nine hundred forty-five thousand, seven hundred sixty-four".