639138246 has 12 divisors (see below), whose sum is σ = 1278400356. Its totient is φ = 213025440.

The previous prime is 639138233. The next prime is 639138301. The reversal of 639138246 is 642831936.

It is a junction number, because it is equal to n+sod(n) for n = 639138198 and 639138207.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 56766 + ... + 67086.

It is an arithmetic number, because the mean of its divisors is an integer number (106533363).

Almost surely, 2^639138246 is an apocalyptic number.

639138246 is an abundant number, since it is smaller than the sum of its proper divisors (639262110).

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

639138246 is an frugal number, since it uses more digits than its factorization.

639138246 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20647 (or 10326 counting only the distinct ones).

The product of its digits is 186624, while the sum is 42.

The square root of 639138246 is about 25281.1836352652. The cubic root of 639138246 is about 861.3869121314.

The spelling of 639138246 in words is "six hundred thirty-nine million, one hundred thirty-eight thousand, two hundred forty-six".