639531392 has 32 divisors (see below), whose sum is σ = 1291538280. Its totient is φ = 315380736.

The previous prime is 639531391. The next prime is 639531401. The reversal of 639531392 is 293135936.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639531391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24878 + ... + 43565.

Almost surely, 2^639531392 is an apocalyptic number.

It is an amenable number.

639531392 is an abundant number, since it is smaller than the sum of its proper divisors (652006888).

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

639531392 is an equidigital number, since it uses as much as digits as its factorization.

639531392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68530 (or 68518 counting only the distinct ones).

The product of its digits is 131220, while the sum is 41.

The square root of 639531392 is about 25288.9579065647. The cubic root of 639531392 is about 861.5634943799.

The spelling of 639531392 in words is "six hundred thirty-nine million, five hundred thirty-one thousand, three hundred ninety-two".