166491 has 12 divisors (see below), whose sum is σ = 259168. Its totient is φ = 102384.

The previous prime is 166487. The next prime is 166541. The reversal of 166491 is 194661.

166491 is a `hidden beast` number, since 16 + 649 + 1 = 666.

166491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 166491 - 2² = 166487 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 166491.

It is not an unprimeable number, because it can be changed into a prime (166471) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 595 + ... + 828.

2¹⁶⁶⁴⁹¹ is an apocalyptic number.

166491 is a deficient number, since it is larger than the sum of its proper divisors (92677).

166491 is a wasteful number, since it uses less digits than its factorization.

166491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1442 (or 1439 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 166491 is about 408.0330868937. The cubic root of 166491 is about 55.0127793996.

Subtracting from 166491 its sum of digits (27), we obtain a square (166464 = 408²).

The spelling of 166491 in words is "one hundred sixty-six thousand, four hundred ninety-one".