166881181 has 4 divisors (see below), whose sum is σ = 166918752. Its totient is φ = 166843612.

The previous prime is 166881179. The next prime is 166881191. The reversal of 166881181 is 181188661.

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.

It is a cyclic number.

It is not a de Polignac number, because 166881181 - 2¹ = 166881179 is a prime.

It is a super-2 number, since 2×166881181² = 55698657143909522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166881191) 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, 11065 + ... + 21358.

It is an arithmetic number, because the mean of its divisors is an integer number (41729688).

Almost surely, 2^166881181 is an apocalyptic number.

It is an amenable number.

166881181 is a deficient number, since it is larger than the sum of its proper divisors (37571).

166881181 is an equidigital number, since it uses as much as digits as its factorization.

166881181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37570.

The product of its digits is 18432, while the sum is 40.

The square root of 166881181 is about 12918.2499201711. The cubic root of 166881181 is about 550.5572105004.

The spelling of 166881181 in words is "one hundred sixty-six million, eight hundred eighty-one thousand, one hundred eighty-one".