668687686291 has 8 divisors (see below), whose sum is σ = 692077082400. Its totient is φ = 645320370240.

The previous prime is 668687686267. The next prime is 668687686301. The reversal of 668687686291 is 192686786866.

668687686291 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 668687686291 - 2²¹ = 668685589139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668687686211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5458375 + ... + 5579536.

It is an arithmetic number, because the mean of its divisors is an integer number (86509635300).

Almost surely, 2^668687686291 is an apocalyptic number.

668687686291 is a deficient number, since it is larger than the sum of its proper divisors (23389396109).

668687686291 is a wasteful number, since it uses less digits than its factorization.

668687686291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11040029.

The product of its digits is 501645312, while the sum is 73.

The spelling of 668687686291 in words is "six hundred sixty-eight billion, six hundred eighty-seven million, six hundred eighty-six thousand, two hundred ninety-one".