639678560 has 48 divisors (see below), whose sum is σ = 1531970496. Its totient is φ = 252361728.

The previous prime is 639678541. The next prime is 639678569. The reversal of 639678560 is 65876936.

639678560 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 639678499 and 639678508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639678569) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15704 + ... + 39063.

It is an arithmetic number, because the mean of its divisors is an integer number (31916052).

Almost surely, 2^639678560 is an apocalyptic number.

It is an amenable number.

639678560 is an abundant number, since it is smaller than the sum of its proper divisors (892291936).

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

639678560 is a wasteful number, since it uses less digits than its factorization.

639678560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54855 (or 54847 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 50.

The square root of 639678560 is about 25291.8674676268. The cubic root of 639678560 is about 861.6295765422.

It can be divided in two parts, 63967 and 8560, that added together give a palindrome (72527).

The spelling of 639678560 in words is "six hundred thirty-nine million, six hundred seventy-eight thousand, five hundred sixty".