668531135865 has 32 divisors (see below), whose sum is σ = 1075490390016. Its totient is φ = 354603919040.

The previous prime is 668531135821. The next prime is 668531135869. The reversal of 668531135865 is 568531135866.

It is a happy number.

It is not a de Polignac number, because 668531135865 - 2⁶ = 668531135801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (668531135869) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14138092 + ... + 14185298.

It is an arithmetic number, because the mean of its divisors is an integer number (33609074688).

Almost surely, 2^668531135865 is an apocalyptic number.

It is an amenable number.

668531135865 is a deficient number, since it is larger than the sum of its proper divisors (406959254151).

668531135865 is a wasteful number, since it uses less digits than its factorization.

668531135865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52349.

The product of its digits is 15552000, while the sum is 57.

Subtracting from 668531135865 its reverse (568531135866), we obtain a palindrome (99999999999).

The spelling of 668531135865 in words is "six hundred sixty-eight billion, five hundred thirty-one million, one hundred thirty-five thousand, eight hundred sixty-five".