666666686666666 has 48 divisors (see below), whose sum is σ = 1213847278087680. Its totient is φ = 273290766708960.

The previous prime is 666666686666621. The next prime is 666666686666699.

666666686666666 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×666666686666666² (a number of 30 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 699523796 + ... + 700476176.

It is an arithmetic number, because the mean of its divisors is an integer number (25288484960160).

Almost surely, 2^{666666686666666} is an apocalyptic number.

666666686666666 is a deficient number, since it is larger than the sum of its proper divisors (547180591421014).

666666686666666 is a wasteful number, since it uses less digits than its factorization.

666666686666666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1262979 (or 1262972 counting only the distinct ones).

The product of its digits is 626913312768, while the sum is 92.

The spelling of 666666686666666 in words is "six hundred sixty-six trillion, six hundred sixty-six billion, six hundred eighty-six million, six hundred sixty-six thousand, six hundred sixty-six".