639822440 has 16 divisors (see below), whose sum is σ = 1439600580. Its totient is φ = 255928960.

The previous prime is 639822439. The next prime is 639822451. The reversal of 639822440 is 44228936.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 638168644 + 1653796 = 25262^2 + 1286^2 .

It is a junction number, because it is equal to n+sod(n) for n = 639822394 and 639822403.

It is an unprimeable number.

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, 7997741 + ... + 7997820.

Almost surely, 2^639822440 is an apocalyptic number.

It is an amenable number.

639822440 is an abundant number, since it is smaller than the sum of its proper divisors (799778140).

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

639822440 is a wasteful number, since it uses less digits than its factorization.

639822440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15995572 (or 15995568 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 38.

The square root of 639822440 is about 25294.7117002744. The cubic root of 639822440 is about 861.6941725115.

The spelling of 639822440 in words is "six hundred thirty-nine million, eight hundred twenty-two thousand, four hundred forty".