639489566064 has 40 divisors (see below), whose sum is σ = 1652231638800. Its totient is φ = 213135198208.

The previous prime is 639489566059. The next prime is 639489566081. The reversal of 639489566064 is 460665984936.

It is a junction number, because it is equal to n+sod(n) for n = 639489565986 and 639489566004.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 503727 + ... + 1238030.

It is an arithmetic number, because the mean of its divisors is an integer number (41305790970).

Almost surely, 2^639489566064 is an apocalyptic number.

It is an amenable number.

639489566064 is an abundant number, since it is smaller than the sum of its proper divisors (1012742072736).

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

639489566064 is a wasteful number, since it uses less digits than its factorization.

639489566064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1749417 (or 1749411 counting only the distinct ones).

The product of its (nonzero) digits is 201553920, while the sum is 66.

Multiplying 639489566064 by its sum of digits (66), we get a palindrome (42206311360224).

The spelling of 639489566064 in words is "six hundred thirty-nine billion, four hundred eighty-nine million, five hundred sixty-six thousand, sixty-four".