166664989 has 4 divisors (see below), whose sum is σ = 167399424. Its totient is φ = 165930556.

The previous prime is 166664963. The next prime is 166665011. The reversal of 166664989 is 989466661.

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, and also an emirpimes, since its reverse is a distinct semiprime: 989466661 = 3623 ⋅273107.

It is a cyclic number.

It is not a de Polignac number, because 166664989 - 2²⁵ = 133110557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166664929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 366877 + ... + 367330.

It is an arithmetic number, because the mean of its divisors is an integer number (41849856).

Almost surely, 2^166664989 is an apocalyptic number.

It is an amenable number.

166664989 is a deficient number, since it is larger than the sum of its proper divisors (734435).

166664989 is an equidigital number, since it uses as much as digits as its factorization.

166664989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 734434.

The product of its digits is 3359232, while the sum is 55.

The square root of 166664989 is about 12909.8795114439. The cubic root of 166664989 is about 550.3193616318.

The spelling of 166664989 in words is "one hundred sixty-six million, six hundred sixty-four thousand, nine hundred eighty-nine".