639662713 has 2 divisors, whose sum is σ = 639662714. Its totient is φ = 639662712.

The previous prime is 639662663. The next prime is 639662731. The reversal of 639662713 is 317266936.

Together with next prime (639662731) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 550700089 + 88962624 = 23467^2 + 9432^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639662713 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 639662713.

It is not a weakly prime, because it can be changed into another prime (639662753) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319831356 + 319831357.

It is an arithmetic number, because the mean of its divisors is an integer number (319831357).

Almost surely, 2^639662713 is an apocalyptic number.

It is an amenable number.

639662713 is a deficient number, since it is larger than the sum of its proper divisors (1).

639662713 is an equidigital number, since it uses as much as digits as its factorization.

639662713 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 43.

The square root of 639662713 is about 25291.5541831656. The cubic root of 639662713 is about 861.6224613245.

The spelling of 639662713 in words is "six hundred thirty-nine million, six hundred sixty-two thousand, seven hundred thirteen".