639939120 has 80 divisors (see below), whose sum is σ = 2070081792. Its totient is φ = 163229440.

The previous prime is 639939101. The next prime is 639939121. The reversal of 639939120 is 21939936.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (639939121) 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, 52446 + ... + 63485.

Almost surely, 2^639939120 is an apocalyptic number.

639939120 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

639939120 is an abundant number, since it is smaller than the sum of its proper divisors (1430142672).

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

639939120 is a wasteful number, since it uses less digits than its factorization.

639939120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115970 (or 115964 counting only the distinct ones).

The product of its (nonzero) digits is 78732, while the sum is 42.

The square root of 639939120 is about 25297.0180060813. The cubic root of 639939120 is about 861.7465497329.

The spelling of 639939120 in words is "six hundred thirty-nine million, nine hundred thirty-nine thousand, one hundred twenty".