18166181 has 4 divisors (see below), whose sum is σ = 19817664. Its totient is φ = 16514700.

The previous prime is 18166171. The next prime is 18166189.

18166181 is nontrivially palindromic in base 10.

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 18166181 - 2⁶ = 18166117 is a prime.

It is a super-2 number, since 2×18166181² = 660020264249522, 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 (18166189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 825725 + ... + 825746.

It is an arithmetic number, because the mean of its divisors is an integer number (4954416).

Almost surely, 2^18166181 is an apocalyptic number.

18166181 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18166181 is a deficient number, since it is larger than the sum of its proper divisors (1651483).

18166181 is a wasteful number, since it uses less digits than its factorization.

18166181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1651482.

The product of its digits is 2304, while the sum is 32.

The square root of 18166181 is about 4262.1803105922. The cubic root of 18166181 is about 262.8781838381.

It can be divided in two parts, 1816 and 6181, that added together give a palindrome (7997).

The spelling of 18166181 in words is "eighteen million, one hundred sixty-six thousand, one hundred eighty-one".