668815 has 16 divisors (see below), whose sum is σ = 931392. Its totient is φ = 451584.

The previous prime is 668813. The next prime is 668821. The reversal of 668815 is 518866.

It is a happy number.

668815 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 668815 - 2¹ = 668813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668813) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3297 + ... + 3493.

It is an arithmetic number, because the mean of its divisors is an integer number (58212).

2⁶⁶⁸⁸¹⁵ is an apocalyptic number.

668815 is a deficient number, since it is larger than the sum of its proper divisors (262577).

668815 is a wasteful number, since it uses less digits than its factorization.

668815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 306.

The product of its digits is 11520, while the sum is 34.

The square root of 668815 is about 817.8111028838. The cubic root of 668815 is about 87.4517829586.

The spelling of 668815 in words is "six hundred sixty-eight thousand, eight hundred fifteen".