639880379780 has 48 divisors (see below), whose sum is σ = 1422872510976. Its totient is φ = 240882654720.

The previous prime is 639880379773. The next prime is 639880379791. The reversal of 639880379780 is 87973088936.

It is a Smith number, since the sum of its digits (68) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (68).

It is a self number, because there is not a number n which added to its sum of digits gives 639880379780.

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, 7706285 + ... + 7788875.

It is an arithmetic number, because the mean of its divisors is an integer number (29643177312).

Almost surely, 2^639880379780 is an apocalyptic number.

It is an amenable number.

639880379780 is an abundant number, since it is smaller than the sum of its proper divisors (782992131196).

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

639880379780 is a wasteful number, since it uses less digits than its factorization.

639880379780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105404 (or 105402 counting only the distinct ones).

The product of its (nonzero) digits is 109734912, while the sum is 68.

The spelling of 639880379780 in words is "six hundred thirty-nine billion, eight hundred eighty million, three hundred seventy-nine thousand, seven hundred eighty".