668888865 has 24 divisors (see below), whose sum is σ = 1186373760. Its totient is φ = 348443424.

The previous prime is 668888861. The next prime is 668888867. The reversal of 668888865 is 568888866.

It is not a de Polignac number, because 668888865 - 2² = 668888861 is a prime.

It is not an unprimeable number, because it can be changed into a prime (668888861) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 170905 + ... + 174774.

It is an arithmetic number, because the mean of its divisors is an integer number (49432240).

Almost surely, 2^668888865 is an apocalyptic number.

It is an amenable number.

668888865 is a deficient number, since it is larger than the sum of its proper divisors (517484895).

668888865 is a wasteful number, since it uses less digits than its factorization.

668888865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345733 (or 345730 counting only the distinct ones).

The product of its digits is 35389440, while the sum is 63.

The square root of 668888865 is about 25862.8858598572. The cubic root of 668888865 is about 874.5500227842.

Subtracting from 668888865 its reverse (568888866), we obtain a palindrome (99999999).

The spelling of 668888865 in words is "six hundred sixty-eight million, eight hundred eighty-eight thousand, eight hundred sixty-five".