639729888 has 288 divisors, whose sum is σ = 2084963328. Its totient is φ = 170956800.

The previous prime is 639729863. The next prime is 639729899. The reversal of 639729888 is 888927936.

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, 5978731 + ... + 5978837.

It is an arithmetic number, because the mean of its divisors is an integer number (7239456).

Almost surely, 2^639729888 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 639729888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1042481664).

639729888 is an abundant number, since it is smaller than the sum of its proper divisors (1445233440).

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

639729888 is a wasteful number, since it uses less digits than its factorization.

639729888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206 (or 191 counting only the distinct ones).

The product of its digits is 10450944, while the sum is 60.

The square root of 639729888 is about 25292.8821607977. The cubic root of 639729888 is about 861.6526217312.

The spelling of 639729888 in words is "six hundred thirty-nine million, seven hundred twenty-nine thousand, eight hundred eighty-eight".