18185 has 4 divisors (see below), whose sum is σ = 21828. Its totient is φ = 14544.

The previous prime is 18181. The next prime is 18191. The reversal of 18185 is 58181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58181 = 73 ⋅797.

It can be written as a sum of positive squares in 2 ways, for example, as 2809 + 15376 = 53^2 + 124^2 .

It is a cyclic number.

It is not a de Polignac number, because 18185 - 2² = 18181 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 18185.

It is not an unprimeable number, because it can be changed into a prime (18181) 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, 1814 + ... + 1823.

It is an arithmetic number, because the mean of its divisors is an integer number (5457).

2¹⁸¹⁸⁵ is an apocalyptic number.

It is an amenable number.

18185 is a deficient number, since it is larger than the sum of its proper divisors (3643).

18185 is an equidigital number, since it uses as much as digits as its factorization.

18185 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3642.

The product of its digits is 320, while the sum is 23.

The square root of 18185 is about 134.8517704741. The cubic root of 18185 is about 26.2968927498.

The spelling of 18185 in words is "eighteen thousand, one hundred eighty-five".