668501879 has 4 divisors (see below), whose sum is σ = 681115176. Its totient is φ = 655888584.

The previous prime is 668501861. The next prime is 668501891. The reversal of 668501879 is 978105866.

It is a happy number.

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 668501879 - 2²⁴ = 651724663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668501809) 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, 6306569 + ... + 6306674.

It is an arithmetic number, because the mean of its divisors is an integer number (170278794).

Almost surely, 2^668501879 is an apocalyptic number.

668501879 is a deficient number, since it is larger than the sum of its proper divisors (12613297).

668501879 is a wasteful number, since it uses less digits than its factorization.

668501879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12613296.

The product of its (nonzero) digits is 725760, while the sum is 50.

The square root of 668501879 is about 25855.4032844201. The cubic root of 668501879 is about 874.3813331250.

The spelling of 668501879 in words is "six hundred sixty-eight million, five hundred one thousand, eight hundred seventy-nine".