666868 has 12 divisors (see below), whose sum is σ = 1173060. Its totient is φ = 331712.

The previous prime is 666857. The next prime is 666871. The reversal of 666868 is 868666.

666868 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 394384 + 272484 = 628^2 + 522^2 .

Its product of digits (82944) is a multiple of the sum of its prime divisors (864).

It is a self number, because there is not a number n which added to its sum of digits gives 666868.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 888 + ... + 1456.

It is an arithmetic number, because the mean of its divisors is an integer number (97755).

2⁶⁶⁶⁸⁶⁸ is an apocalyptic number.

It is an amenable number.

666868 is a deficient number, since it is larger than the sum of its proper divisors (506192).

666868 is a wasteful number, since it uses less digits than its factorization.

666868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 866 (or 864 counting only the distinct ones).

The product of its digits is 82944, while the sum is 40.

The square root of 666868 is about 816.6198626044. The cubic root of 666868 is about 87.3668396319.

The spelling of 666868 in words is "six hundred sixty-six thousand, eight hundred sixty-eight".