639090656 has 48 divisors (see below), whose sum is σ = 1354132080. Its totient is φ = 295802880.

The previous prime is 639090649. The next prime is 639090671. The reversal of 639090656 is 656090936.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23555 + ... + 42813.

It is an arithmetic number, because the mean of its divisors is an integer number (28211085).

Almost surely, 2^639090656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639090656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (677066040).

639090656 is an abundant number, since it is smaller than the sum of its proper divisors (715041424).

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

639090656 is a wasteful number, since it uses less digits than its factorization.

639090656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19347 (or 19339 counting only the distinct ones).

The product of its (nonzero) digits is 262440, while the sum is 44.

The square root of 639090656 is about 25280.2424039011. The cubic root of 639090656 is about 861.3655320826.

The spelling of 639090656 in words is "six hundred thirty-nine million, ninety thousand, six hundred fifty-six".