166989 has 4 divisors (see below), whose sum is σ = 222656. Its totient is φ = 111324.

The previous prime is 166987. The next prime is 167009. The reversal of 166989 is 989661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 166989 - 2¹ = 166987 is a prime.

It is a super-2 number, since 2×166989² = 55770652242, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27829 + ... + 27834.

It is an arithmetic number, because the mean of its divisors is an integer number (55664).

2¹⁶⁶⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

166989 is a deficient number, since it is larger than the sum of its proper divisors (55667).

166989 is an equidigital number, since it uses as much as digits as its factorization.

166989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55666.

The product of its digits is 23328, while the sum is 39.

The square root of 166989 is about 408.6428758709. The cubic root of 166989 is about 55.0675753423.

The spelling of 166989 in words is "one hundred sixty-six thousand, nine hundred eighty-nine".