166666666685 has 12 divisors (see below), whose sum is σ = 205551505908. Its totient is φ = 129729724416.

The previous prime is 166666666669. The next prime is 166666666709. The reversal of 166666666685 is 586666666661.

It can be written as a sum of positive squares in 6 ways, for example, as 55098642361 + 111568024324 = 234731^2 + 334018^2 .

It is not a de Polignac number, because 166666666685 - 2⁴ = 166666666669 is a prime.

It is a super-4 number, since 4×166666666685⁴ (a number of 46 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12167492 + ... + 12181181.

It is an arithmetic number, because the mean of its divisors is an integer number (17129292159).

Almost surely, 2^166666666685 is an apocalyptic number.

It is an amenable number.

166666666685 is a deficient number, since it is larger than the sum of its proper divisors (38884839223).

166666666685 is an equidigital number, since it uses as much as digits as its factorization.

166666666685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24348752 (or 24348715 counting only the distinct ones).

The product of its digits is 403107840, while the sum is 68.

The spelling of 166666666685 in words is "one hundred sixty-six billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred eighty-five".