18115 has 4 divisors (see below), whose sum is σ = 21744.
Its totient is φ = 14488.
The previous prime is 18097. The next prime is 18119. The reversal of 18115 is 51181.
It is a semiprime because it is the product of two primes.
It is a cyclic number.
It is not a de Polignac number, because 18115 - 27 = 17987 is a prime.
It is a Duffinian number.
It is a plaindrome in base 11 and base 15.
It is not an unprimeable number, because it can be changed into a prime (18119) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1807 + ... + 1816.
It is an arithmetic number, because the mean of its divisors is an integer number (5436).
218115 is an apocalyptic number.
18115 is a deficient number, since it is larger than the sum of its proper divisors (3629).
18115 is an equidigital number, since it uses as much as digits as its factorization.
18115 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 3628.
The product of its digits is 40, while the sum is 16.
The square root of 18115 is about 134.5919759867.
The cubic root of 18115 is about 26.2631075884.
Adding to 18115 its reverse (51181), we get a palindrome (69296).
It can be divided in two parts, 181 and 15, that added together give a square (196 = 142).
The spelling of 18115 in words is "eighteen thousand, one hundred fifteen".