639743972 has 12 divisors (see below), whose sum is σ = 1279488000. Its totient is φ = 274175976.

The previous prime is 639743947. The next prime is 639743977. The reversal of 639743972 is 279347936.

639743972 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

639743972 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 639743972.

It is not an unprimeable number, because it can be changed into a prime (639743977) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11423972 + ... + 11424027.

It is an arithmetic number, because the mean of its divisors is an integer number (106624000).

Almost surely, 2^639743972 is an apocalyptic number.

It is an amenable number.

639743972 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

639743972 is a wasteful number, since it uses less digits than its factorization.

639743972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22848010 (or 22848008 counting only the distinct ones).

The product of its digits is 1714608, while the sum is 50.

The square root of 639743972 is about 25293.1605775158. The cubic root of 639743972 is about 861.6589449346.

The spelling of 639743972 in words is "six hundred thirty-nine million, seven hundred forty-three thousand, nine hundred seventy-two".