668536613 has 2 divisors, whose sum is σ = 668536614. Its totient is φ = 668536612.

The previous prime is 668536597. The next prime is 668536619. The reversal of 668536613 is 316635866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 666775684 + 1760929 = 25822^2 + 1327^2 .

It is a cyclic number.

It is not a de Polignac number, because 668536613 - 2⁴ = 668536597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668536619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334268306 + 334268307.

It is an arithmetic number, because the mean of its divisors is an integer number (334268307).

Almost surely, 2^668536613 is an apocalyptic number.

It is an amenable number.

668536613 is a deficient number, since it is larger than the sum of its proper divisors (1).

668536613 is an equidigital number, since it uses as much as digits as its factorization.

668536613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 466560, while the sum is 44.

The square root of 668536613 is about 25856.0749728183. The cubic root of 668536613 is about 874.3964765555.

The spelling of 668536613 in words is "six hundred sixty-eight million, five hundred thirty-six thousand, six hundred thirteen".