639594873 has 10 divisors (see below), whose sum is σ = 955444314. Its totient is φ = 426396528.

The previous prime is 639594871. The next prime is 639594881. The reversal of 639594873 is 378495936.

It can be written as a sum of positive squares in only one way, i.e., 396328464 + 243266409 = 19908^2 + 15597^2 .

It is not a de Polignac number, because 639594873 - 2¹ = 639594871 is a prime.

It is a super-2 number, since 2×639594873² = 818163203135772258, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (639594871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 3948036 + ... + 3948197.

Almost surely, 2^639594873 is an apocalyptic number.

It is an amenable number.

639594873 is a deficient number, since it is larger than the sum of its proper divisors (315849441).

639594873 is an equidigital number, since it uses as much as digits as its factorization.

639594873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7896245 (or 7896236 counting only the distinct ones).

The product of its digits is 4898880, while the sum is 54.

The square root of 639594873 is about 25290.2129884270. The cubic root of 639594873 is about 861.5920002012.

The spelling of 639594873 in words is "six hundred thirty-nine million, five hundred ninety-four thousand, eight hundred seventy-three".