668316613 has 2 divisors, whose sum is σ = 668316614. Its totient is φ = 668316612.

The previous prime is 668316611. The next prime is 668316619. The reversal of 668316613 is 316613866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 426918244 + 241398369 = 20662^2 + 15537^2 .

It is a cyclic number.

It is not a de Polignac number, because 668316613 - 2¹ = 668316611 is a prime.

Together with 668316611, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668316611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334158306 + 334158307.

It is an arithmetic number, because the mean of its divisors is an integer number (334158307).

Almost surely, 2^668316613 is an apocalyptic number.

It is an amenable number.

668316613 is a deficient number, since it is larger than the sum of its proper divisors (1).

668316613 is an equidigital number, since it uses as much as digits as its factorization.

668316613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 40.

The square root of 668316613 is about 25851.8203034138. The cubic root of 668316613 is about 874.3005514527.

The spelling of 668316613 in words is "six hundred sixty-eight million, three hundred sixteen thousand, six hundred thirteen".