639997104 has 20 divisors (see below), whose sum is σ = 1653325976. Its totient is φ = 213332352.

The previous prime is 639997081. The next prime is 639997109. The reversal of 639997104 is 401799936.

It is a Harshad number since it is a multiple of its sum of digits (48), and also a Moran number because the ratio is a prime number: 13333273 = 639997104 / (6 + 3 + 9 + 9 + 9 + 7 + 1 + 0 + 4).

It is not an unprimeable number, because it can be changed into a prime (639997109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6666589 + ... + 6666684.

Almost surely, 2^639997104 is an apocalyptic number.

It is an amenable number.

639997104 is an abundant number, since it is smaller than the sum of its proper divisors (1013328872).

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

639997104 is a wasteful number, since it uses less digits than its factorization.

639997104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13333284 (or 13333278 counting only the distinct ones).

The product of its (nonzero) digits is 367416, while the sum is 48.

The square root of 639997104 is about 25298.1640440566. The cubic root of 639997104 is about 861.7725761685.

The spelling of 639997104 in words is "six hundred thirty-nine million, nine hundred ninety-seven thousand, one hundred four".