166666666681 has 8 divisors (see below), whose sum is σ = 167020359200. Its totient is φ = 166313347200.

The previous prime is 166666666669. The next prime is 166666666709. The reversal of 166666666681 is 186666666661.

166666666681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166666666681 is a prime.

It is a super-2 number, since 2×166666666681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166666666601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 810505 + ... + 995113.

It is an arithmetic number, because the mean of its divisors is an integer number (20877544900).

Almost surely, 2^166666666681 is an apocalyptic number.

It is an amenable number.

166666666681 is a deficient number, since it is larger than the sum of its proper divisors (353692519).

166666666681 is a wasteful number, since it uses less digits than its factorization.

166666666681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186519.

The product of its digits is 80621568, while the sum is 64.

The spelling of 166666666681 in words is "one hundred sixty-six billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred eighty-one".