166681688 has 8 divisors (see below), whose sum is σ = 312528180. Its totient is φ = 83340840.

The previous prime is 166681643. The next prime is 166681709. The reversal of 166681688 is 886186661.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×166681688² = 55565570229058688, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10417598 + ... + 10417613.

Almost surely, 2^166681688 is an apocalyptic number.

It is an amenable number.

166681688 is a deficient number, since it is larger than the sum of its proper divisors (145846492).

166681688 is a wasteful number, since it uses less digits than its factorization.

166681688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20835217 (or 20835213 counting only the distinct ones).

The product of its digits is 663552, while the sum is 50.

The square root of 166681688 is about 12910.5262479885. The cubic root of 166681688 is about 550.3377407690.

The spelling of 166681688 in words is "one hundred sixty-six million, six hundred eighty-one thousand, six hundred eighty-eight".