166400189 has 2 divisors, whose sum is σ = 166400190. Its totient is φ = 166400188.

The previous prime is 166400183. The next prime is 166400191. The reversal of 166400189 is 981004661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160224964 + 6175225 = 12658^2 + 2485^2 .

It is a cyclic number.

It is not a de Polignac number, because 166400189 - 2¹² = 166396093 is a prime.

Together with 166400191, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166400183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83200094 + 83200095.

It is an arithmetic number, because the mean of its divisors is an integer number (83200095).

Almost surely, 2^166400189 is an apocalyptic number.

It is an amenable number.

166400189 is a deficient number, since it is larger than the sum of its proper divisors (1).

166400189 is an equidigital number, since it uses as much as digits as its factorization.

166400189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 166400189 is about 12899.6197230771. The cubic root of 166400189 is about 550.0277550732.

The spelling of 166400189 in words is "one hundred sixty-six million, four hundred thousand, one hundred eighty-nine".