639221408 has 48 divisors (see below), whose sum is σ = 1513955520. Its totient is φ = 259531776.

The previous prime is 639221357. The next prime is 639221413. The reversal of 639221408 is 804122936.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70841 + ... + 79352.

It is an arithmetic number, because the mean of its divisors is an integer number (31540740).

Almost surely, 2^639221408 is an apocalyptic number.

It is an amenable number.

639221408 is an abundant number, since it is smaller than the sum of its proper divisors (874734112).

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

639221408 is a wasteful number, since it uses less digits than its factorization.

639221408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150229 (or 150221 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 639221408 is about 25282.8283227965. The cubic root of 639221408 is about 861.4242705339.

The spelling of 639221408 in words is "six hundred thirty-nine million, two hundred twenty-one thousand, four hundred eight".