639798013 has 2 divisors, whose sum is σ = 639798014. Its totient is φ = 639798012.

The previous prime is 639797909. The next prime is 639798017. The reversal of 639798013 is 310897936.

639798013 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 607228164 + 32569849 = 24642^2 + 5707^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639798013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639798017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319899006 + 319899007.

It is an arithmetic number, because the mean of its divisors is an integer number (319899007).

Almost surely, 2^639798013 is an apocalyptic number.

It is an amenable number.

639798013 is a deficient number, since it is larger than the sum of its proper divisors (1).

639798013 is an equidigital number, since it uses as much as digits as its factorization.

639798013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 244944, while the sum is 46.

The square root of 639798013 is about 25294.2288477036. The cubic root of 639798013 is about 861.6832065152.

The spelling of 639798013 in words is "six hundred thirty-nine million, seven hundred ninety-eight thousand, thirteen".