666666668 has 24 divisors (see below), whose sum is σ = 1195315968. Its totient is φ = 325167696.

The previous prime is 666666667. The next prime is 666666691. The reversal of 666666668 is 866666666.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (666666667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 167105 + ... + 171047.

It is an arithmetic number, because the mean of its divisors is an integer number (49804832).

Almost surely, 2^666666668 is an apocalyptic number.

It is an amenable number.

666666668 is a deficient number, since it is larger than the sum of its proper divisors (528649300).

666666668 is a wasteful number, since it uses less digits than its factorization.

666666668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4973 (or 4971 counting only the distinct ones).

The product of its digits is 13436928, while the sum is 56.

The square root of 666666668 is about 25819.8890005360. The cubic root of 666666668 is about 873.5804653187.

The spelling of 666666668 in words is "six hundred sixty-six million, six hundred sixty-six thousand, six hundred sixty-eight".