639754631 has 2 divisors, whose sum is σ = 639754632. Its totient is φ = 639754630.

The previous prime is 639754627. The next prime is 639754649. The reversal of 639754631 is 136457936.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639754631 - 2² = 639754627 is a prime.

It is a super-2 number, since 2×639754631² = 818571975771892322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639754651) 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 as a sum of consecutive naturals, namely, 319877315 + 319877316.

It is an arithmetic number, because the mean of its divisors is an integer number (319877316).

Almost surely, 2^639754631 is an apocalyptic number.

639754631 is a deficient number, since it is larger than the sum of its proper divisors (1).

639754631 is an equidigital number, since it uses as much as digits as its factorization.

639754631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 408240, while the sum is 44.

The square root of 639754631 is about 25293.3712857737. The cubic root of 639754631 is about 861.6637303759.

The spelling of 639754631 in words is "six hundred thirty-nine million, seven hundred fifty-four thousand, six hundred thirty-one".