166386989 has 2 divisors, whose sum is σ = 166386990. Its totient is φ = 166386988.

The previous prime is 166386947. The next prime is 166387019. The reversal of 166386989 is 989683661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151044100 + 15342889 = 12290^2 + 3917^2 .

It is a cyclic number.

It is not a de Polignac number, because 166386989 - 2²⁴ = 149609773 is a prime.

It is a super-2 number, since 2×166386989² = 55369260216972242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166386919) 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 as a sum of consecutive naturals, namely, 83193494 + 83193495.

It is an arithmetic number, because the mean of its divisors is an integer number (83193495).

Almost surely, 2^166386989 is an apocalyptic number.

It is an amenable number.

166386989 is a deficient number, since it is larger than the sum of its proper divisors (1).

166386989 is an equidigital number, since it uses as much as digits as its factorization.

166386989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3359232, while the sum is 56.

The square root of 166386989 is about 12899.1080699403. The cubic root of 166386989 is about 550.0132107020.

The spelling of 166386989 in words is "one hundred sixty-six million, three hundred eighty-six thousand, nine hundred eighty-nine".