639809289 has 12 divisors (see below), whose sum is σ = 1056193216. Its totient is φ = 365605272.

The previous prime is 639809273. The next prime is 639809293. The reversal of 639809289 is 982908936.

It is not a de Polignac number, because 639809289 - 2⁴ = 639809273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639808289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5077789 + ... + 5077914.

Almost surely, 2^639809289 is an apocalyptic number.

It is an amenable number.

639809289 is a deficient number, since it is larger than the sum of its proper divisors (416383927).

639809289 is a wasteful number, since it uses less digits than its factorization.

639809289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10155716 (or 10155713 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 54.

The square root of 639809289 is about 25294.4517434160. The cubic root of 639809289 is about 861.6882686768.

The spelling of 639809289 in words is "six hundred thirty-nine million, eight hundred nine thousand, two hundred eighty-nine".