639090671 has 2 divisors, whose sum is σ = 639090672. Its totient is φ = 639090670.

The previous prime is 639090649. The next prime is 639090701. The reversal of 639090671 is 176090936.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639090671 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639090601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319545335 + 319545336.

It is an arithmetic number, because the mean of its divisors is an integer number (319545336).

Almost surely, 2^639090671 is an apocalyptic number.

639090671 is a deficient number, since it is larger than the sum of its proper divisors (1).

639090671 is an equidigital number, since it uses as much as digits as its factorization.

639090671 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 61236, while the sum is 41.

The square root of 639090671 is about 25280.2427005755. The cubic root of 639090671 is about 861.3655388216.

The spelling of 639090671 in words is "six hundred thirty-nine million, ninety thousand, six hundred seventy-one".