639123287 has 16 divisors (see below), whose sum is σ = 730321920. Its totient is φ = 553634400.

The previous prime is 639123271. The next prime is 639123299. The reversal of 639123287 is 782321936.

It is not a de Polignac number, because 639123287 - 2⁴ = 639123271 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639123217) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63362 + ... + 72752.

It is an arithmetic number, because the mean of its divisors is an integer number (45645120).

Almost surely, 2^639123287 is an apocalyptic number.

639123287 is a deficient number, since it is larger than the sum of its proper divisors (91198633).

639123287 is a wasteful number, since it uses less digits than its factorization.

639123287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9694.

The product of its digits is 108864, while the sum is 41.

The square root of 639123287 is about 25280.8877810887. The cubic root of 639123287 is about 861.3801918391.

The spelling of 639123287 in words is "six hundred thirty-nine million, one hundred twenty-three thousand, two hundred eighty-seven".