668360813 has 2 divisors, whose sum is σ = 668360814. Its totient is φ = 668360812.

The previous prime is 668360779. The next prime is 668360863. The reversal of 668360813 is 318063866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 476898244 + 191462569 = 21838^2 + 13837^2 .

It is a cyclic number.

It is not a de Polignac number, because 668360813 - 2¹⁴ = 668344429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668360863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334180406 + 334180407.

It is an arithmetic number, because the mean of its divisors is an integer number (334180407).

Almost surely, 2^668360813 is an apocalyptic number.

It is an amenable number.

668360813 is a deficient number, since it is larger than the sum of its proper divisors (1).

668360813 is an equidigital number, since it uses as much as digits as its factorization.

668360813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 668360813 is about 25852.6751613832. The cubic root of 668360813 is about 874.3198253676.

The spelling of 668360813 in words is "six hundred sixty-eight million, three hundred sixty thousand, eight hundred thirteen".