639020889 has 24 divisors (see below), whose sum is σ = 995201480. Its totient is φ = 392781312.

The previous prime is 639020881. The next prime is 639020911. The reversal of 639020889 is 988020936.

639020889 is a `hidden beast` number, since 639 + 0 + 2 + 0 + 8 + 8 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1710864 + 637310025 = 1308^2 + 25245^2 .

It is not a de Polignac number, because 639020889 - 2³ = 639020881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639020881) 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, 115347 + ... + 120759.

Almost surely, 2^639020889 is an apocalyptic number.

It is an amenable number.

639020889 is a deficient number, since it is larger than the sum of its proper divisors (356180591).

639020889 is a wasteful number, since it uses less digits than its factorization.

639020889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6441 (or 6438 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The square root of 639020889 is about 25278.8624941867. The cubic root of 639020889 is about 861.3341869855.

The spelling of 639020889 in words is "six hundred thirty-nine million, twenty thousand, eight hundred eighty-nine".