639934764 has 96 divisors (see below), whose sum is σ = 1772305920. Its totient is φ = 175838208.

The previous prime is 639934759. The next prime is 639934781. The reversal of 639934764 is 467439936.

It is a hoax number, since the sum of its digits (51) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1078852 + ... + 1079444.

It is an arithmetic number, because the mean of its divisors is an integer number (18461520).

Almost surely, 2^639934764 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639934764, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (886152960).

639934764 is an abundant number, since it is smaller than the sum of its proper divisors (1132371156).

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

639934764 is a wasteful number, since it uses less digits than its factorization.

639934764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1079 (or 1077 counting only the distinct ones).

The product of its digits is 2939328, while the sum is 51.

The square root of 639934764 is about 25296.9319088304. The cubic root of 639934764 is about 861.7445944550.

The spelling of 639934764 in words is "six hundred thirty-nine million, nine hundred thirty-four thousand, seven hundred sixty-four".