639642339 has 24 divisors (see below), whose sum is σ = 1095028480. Its totient is φ = 365508936.

The previous prime is 639642331. The next prime is 639642343. The reversal of 639642339 is 933246936.

639642339 is a `hidden beast` number, since 639 + 6 + 4 + 2 + 3 + 3 + 9 = 666.

It is not a de Polignac number, because 639642339 - 2³ = 639642331 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 639642294 and 639642303.

It is not an unprimeable number, because it can be changed into a prime (639642331) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 186319 + ... + 189720.

Almost surely, 2^639642339 is an apocalyptic number.

639642339 is a deficient number, since it is larger than the sum of its proper divisors (455386141).

639642339 is an equidigital number, since it uses as much as digits as its factorization.

639642339 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376061 (or 376049 counting only the distinct ones).

The product of its digits is 629856, while the sum is 45.

The square root of 639642339 is about 25291.1513972773. The cubic root of 639642339 is about 861.6133133355.

The spelling of 639642339 in words is "six hundred thirty-nine million, six hundred forty-two thousand, three hundred thirty-nine".