656638013 has 2 divisors, whose sum is σ = 656638014. Its totient is φ = 656638012.

The previous prime is 656637979. The next prime is 656638027. The reversal of 656638013 is 310836656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 654438724 + 2199289 = 25582^2 + 1483^2 .

It is a cyclic number.

It is not a de Polignac number, because 656638013 - 2⁸ = 656637757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656638093) 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, 328319006 + 328319007.

It is an arithmetic number, because the mean of its divisors is an integer number (328319007).

Almost surely, 2^656638013 is an apocalyptic number.

It is an amenable number.

656638013 is a deficient number, since it is larger than the sum of its proper divisors (1).

656638013 is an equidigital number, since it uses as much as digits as its factorization.

656638013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 38.

The square root of 656638013 is about 25624.9490340957. The cubic root of 656638013 is about 869.1778964972.

The spelling of 656638013 in words is "six hundred fifty-six million, six hundred thirty-eight thousand, thirteen".