166986666685 has 4 divisors (see below), whose sum is σ = 200384000028. Its totient is φ = 133589333344.

The previous prime is 166986666643. The next prime is 166986666697. The reversal of 166986666685 is 586666689661.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 79599029689 + 87387636996 = 282133^2 + 295614^2 .

It is a cyclic number.

It is not a de Polignac number, because 166986666685 - 2³⁷ = 29547713213 is a prime.

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 3 ways as a sum of consecutive naturals, for example, 16698666664 + ... + 16698666673.

It is an arithmetic number, because the mean of its divisors is an integer number (50096000007).

Almost surely, 2^166986666685 is an apocalyptic number.

It is an amenable number.

166986666685 is a deficient number, since it is larger than the sum of its proper divisors (33397333343).

166986666685 is an equidigital number, since it uses as much as digits as its factorization.

166986666685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33397333342.

The product of its digits is 806215680, while the sum is 73.

The spelling of 166986666685 in words is "one hundred sixty-six billion, nine hundred eighty-six million, six hundred sixty-six thousand, six hundred eighty-five".