668765291 has 2 divisors, whose sum is σ = 668765292. Its totient is φ = 668765290.

The previous prime is 668765243. The next prime is 668765297. The reversal of 668765291 is 192567866.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668765291 is a prime.

It is not a weakly prime, because it can be changed into another prime (668765297) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334382645 + 334382646.

It is an arithmetic number, because the mean of its divisors is an integer number (334382646).

Almost surely, 2^668765291 is an apocalyptic number.

668765291 is a deficient number, since it is larger than the sum of its proper divisors (1).

668765291 is an equidigital number, since it uses as much as digits as its factorization.

668765291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 50.

The square root of 668765291 is about 25860.4967276346. The cubic root of 668765291 is about 874.4961631641.

The spelling of 668765291 in words is "six hundred sixty-eight million, seven hundred sixty-five thousand, two hundred ninety-one".