639591680 has 432 divisors, whose sum is σ = 2108426880. Its totient is φ = 180486144.

The previous prime is 639591671. The next prime is 639591727. The reversal of 639591680 is 86195936.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 33662711 + ... + 33662729.

Almost surely, 2^639591680 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 639591680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1054213440).

639591680 is an abundant number, since it is smaller than the sum of its proper divisors (1468835200).

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

639591680 is a wasteful number, since it uses less digits than its factorization.

639591680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94 (or 63 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 47.

The square root of 639591680 is about 25290.1498611614. The cubic root of 639591680 is about 861.5905664458.

The spelling of 639591680 in words is "six hundred thirty-nine million, five hundred ninety-one thousand, six hundred eighty".