668865 has 32 divisors (see below), whose sum is σ = 1178496. Its totient is φ = 322560.

The previous prime is 668851. The next prime is 668867. The reversal of 668865 is 568866.

It is not a de Polignac number, because 668865 - 2⁷ = 668737 is a prime.

It is a Curzon number.

It is a zygodrome in base 6.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 668865.

It is not an unprimeable number, because it can be changed into a prime (668867) 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, 10935 + ... + 10995.

It is an arithmetic number, because the mean of its divisors is an integer number (36828).

2⁶⁶⁸⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

668865 is a deficient number, since it is larger than the sum of its proper divisors (509631).

668865 is a wasteful number, since it uses less digits than its factorization.

668865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129.

The product of its digits is 69120, while the sum is 39.

The square root of 668865 is about 817.8416717189. The cubic root of 668865 is about 87.4539621762.

Subtracting from 668865 its reverse (568866), we obtain a palindrome (99999).

The spelling of 668865 in words is "six hundred sixty-eight thousand, eight hundred sixty-five".