666666666 has 32 divisors (see below), whose sum is σ = 1521526080. Its totient is φ = 216215568.

The previous prime is 666666653. The next prime is 666666667.

666666666 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

666666666 is a modest number, since divided by 66666 gives 6666 as remainder.

666666666 is a nontrivial repdigit in base 10.

It is a plaindrome in base 10.

It is a nialpdrome in base 10.

It is a zygodrome 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 15 ways as a sum of consecutive naturals, for example, 164836 + ... + 168831.

It is an arithmetic number, because the mean of its divisors is an integer number (47547690).

Almost surely, 2^666666666 is an apocalyptic number.

666666666 is an abundant number, since it is smaller than the sum of its proper divisors (854859414).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666666666 is a wasteful number, since it uses less digits than its factorization.

666666666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333715 (or 333709 counting only the distinct ones).

The product of its digits is 10077696, while the sum is 54.

The square root of 666666666 is about 25819.8889618062. Note that the first 3 decimals coincide. The cubic root of 666666666 is about 873.5804644451.

The spelling of 666666666 in words is "six hundred sixty-six million, six hundred sixty-six thousand, six hundred sixty-six".