166172389 has 2 divisors, whose sum is σ = 166172390. Its totient is φ = 166172388.

The previous prime is 166172317. The next prime is 166172443. The reversal of 166172389 is 983271661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135536164 + 30636225 = 11642^2 + 5535^2 .

It is a cyclic number.

It is not a de Polignac number, because 166172389 - 2⁹ = 166171877 is a prime.

It is a super-2 number, since 2×166172389² = 55226525731934642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166173389) 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, 83086194 + 83086195.

It is an arithmetic number, because the mean of its divisors is an integer number (83086195).

Almost surely, 2^166172389 is an apocalyptic number.

It is an amenable number.

166172389 is a deficient number, since it is larger than the sum of its proper divisors (1).

166172389 is an equidigital number, since it uses as much as digits as its factorization.

166172389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 43.

The square root of 166172389 is about 12890.7869814065. The cubic root of 166172389 is about 549.7766464991.

The spelling of 166172389 in words is "one hundred sixty-six million, one hundred seventy-two thousand, three hundred eighty-nine".