668311291 has 4 divisors (see below), whose sum is σ = 680920992. Its totient is φ = 655701592.

The previous prime is 668311261. The next prime is 668311307. The reversal of 668311291 is 192113866.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 668311291 - 2²⁷ = 534093563 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 668311291.

It is not an unprimeable number, because it can be changed into a prime (668311201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6304771 + ... + 6304876.

It is an arithmetic number, because the mean of its divisors is an integer number (170230248).

Almost surely, 2^668311291 is an apocalyptic number.

668311291 is a deficient number, since it is larger than the sum of its proper divisors (12609701).

668311291 is a wasteful number, since it uses less digits than its factorization.

668311291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12609700.

The product of its digits is 15552, while the sum is 37.

The square root of 668311291 is about 25851.7173704185. The cubic root of 668311291 is about 874.2982306765.

The spelling of 668311291 in words is "six hundred sixty-eight million, three hundred eleven thousand, two hundred ninety-one".