166681287 has 16 divisors (see below), whose sum is σ = 252679680. Its totient is φ = 108535896.

The previous prime is 166681279. The next prime is 166681289. The reversal of 166681287 is 782186661.

It is a happy number.

It is not a de Polignac number, because 166681287 - 2³ = 166681279 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166681289) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70623 + ... + 72944.

It is an arithmetic number, because the mean of its divisors is an integer number (15792480).

Almost surely, 2^166681287 is an apocalyptic number.

166681287 is a deficient number, since it is larger than the sum of its proper divisors (85998393).

166681287 is a wasteful number, since it uses less digits than its factorization.

166681287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143619 (or 143613 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 166681287 is about 12910.5107180158. The cubic root of 166681287 is about 550.3372994376.

It can be divided in two parts, 16668 and 1287, that added together give a triangular number (17955 = T₁₈₉).

The spelling of 166681287 in words is "one hundred sixty-six million, six hundred eighty-one thousand, two hundred eighty-seven".