639988375 has 32 divisors (see below), whose sum is σ = 910780416. Its totient is φ = 444787200.

The previous prime is 639988357. The next prime is 639988379. The reversal of 639988375 is 573889936.

639988375 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-639988375 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639988379) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16042 + ... + 39208.

It is an arithmetic number, because the mean of its divisors is an integer number (28461888).

Almost surely, 2^639988375 is an apocalyptic number.

639988375 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

639988375 is a deficient number, since it is larger than the sum of its proper divisors (270792041).

639988375 is a wasteful number, since it uses less digits than its factorization.

639988375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23212 (or 23202 counting only the distinct ones).

The product of its digits is 9797760, while the sum is 58.

The square root of 639988375 is about 25297.9915210674. The cubic root of 639988375 is about 861.7686582096.

The spelling of 639988375 in words is "six hundred thirty-nine million, nine hundred eighty-eight thousand, three hundred seventy-five".