166689 has 6 divisors (see below), whose sum is σ = 240786. Its totient is φ = 111120.

The previous prime is 166679. The next prime is 166693. The reversal of 166689 is 986661.

It can be written as a sum of positive squares in only one way, i.e., 166464 + 225 = 408^2 + 15^2 .

It is not a de Polignac number, because 166689 - 2⁵ = 166657 is a prime.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (166609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9252 + ... + 9269.

It is an arithmetic number, because the mean of its divisors is an integer number (40131).

2¹⁶⁶⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

166689 is a deficient number, since it is larger than the sum of its proper divisors (74097).

166689 is a wasteful number, since it uses less digits than its factorization.

166689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18527 (or 18524 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 166689 is about 408.2756421831. The cubic root of 166689 is about 55.0345788065.

The spelling of 166689 in words is "one hundred sixty-six thousand, six hundred eighty-nine".