639918888 has 64 divisors (see below), whose sum is σ = 1831680000. Its totient is φ = 182500032.

The previous prime is 639918883. The next prime is 639918893. The reversal of 639918888 is 888819936.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (639918883) and next prime (639918893).

It is not an unprimeable number, because it can be changed into a prime (639918883) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 97453 + ... + 103811.

It is an arithmetic number, because the mean of its divisors is an integer number (28620000).

Almost surely, 2^639918888 is an apocalyptic number.

It is an amenable number.

639918888 is an abundant number, since it is smaller than the sum of its proper divisors (1191761112).

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

639918888 is a wasteful number, since it uses less digits than its factorization.

639918888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6974 (or 6970 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 60.

The square root of 639918888 is about 25296.6181138902. The cubic root of 639918888 is about 861.7374681191.

The spelling of 639918888 in words is "six hundred thirty-nine million, nine hundred eighteen thousand, eight hundred eighty-eight".