166222161 has 18 divisors (see below), whose sum is σ = 279299202. Its totient is φ = 94983840.

The previous prime is 166222153. The next prime is 166222163. The reversal of 166222161 is 161222661.

166222161 is a `hidden beast` number, since 16 + 622 + 21 + 6 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 164634561 + 1587600 = 12831^2 + 1260^2 .

It is not a de Polignac number, because 166222161 - 2³ = 166222153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (166222163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 188020 + ... + 188901.

Almost surely, 2^166222161 is an apocalyptic number.

It is an amenable number.

166222161 is a deficient number, since it is larger than the sum of its proper divisors (113077041).

166222161 is a wasteful number, since it uses less digits than its factorization.

166222161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376941 (or 376931 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 166222161 is about 12892.7173629146. The cubic root of 166222161 is about 549.8315307710.

The spelling of 166222161 in words is "one hundred sixty-six million, two hundred twenty-two thousand, one hundred sixty-one".