18111 has 4 divisors (see below), whose sum is σ = 24152. Its totient is φ = 12072.

The previous prime is 18097. The next prime is 18119. The reversal of 18111 is 11181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11181 = 3 ⋅3727.

It is not a de Polignac number, because 18111 - 2⁶ = 18047 is a prime.

It is a D-number.

It is a Duffinian number.

18111 is a modest number, since divided by 111 gives 18 as remainder.

It is a plaindrome in base 16.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18119) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3016 + ... + 3021.

It is an arithmetic number, because the mean of its divisors is an integer number (6038).

2¹⁸¹¹¹ is an apocalyptic number.

18111 is a deficient number, since it is larger than the sum of its proper divisors (6041).

18111 is an equidigital number, since it uses as much as digits as its factorization.

18111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6040.

The product of its digits is 8, while the sum is 12.

The square root of 18111 is about 134.5771154394. The cubic root of 18111 is about 26.2611743808.

Adding to 18111 its reverse (11181), we get a palindrome (29292).

It can be divided in two parts, 181 and 11, that multiplied together give a palindrome (1991).

The spelling of 18111 in words is "eighteen thousand, one hundred eleven".