639417688 has 64 divisors (see below), whose sum is σ = 1484400960. Its totient is φ = 251444736.

The previous prime is 639417661. The next prime is 639417743. The reversal of 639417688 is 886714936.

It is a happy number.

639417688 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 123406 + ... + 128482.

It is an arithmetic number, because the mean of its divisors is an integer number (23193765).

Almost surely, 2^639417688 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 639417688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (742200480).

639417688 is an abundant number, since it is smaller than the sum of its proper divisors (844983272).

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

639417688 is a wasteful number, since it uses less digits than its factorization.

639417688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5276 (or 5272 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 52.

The square root of 639417688 is about 25286.7097108343. The cubic root of 639417688 is about 861.5124314594.

The spelling of 639417688 in words is "six hundred thirty-nine million, four hundred seventeen thousand, six hundred eighty-eight".