18187 has 4 divisors (see below), whose sum is σ = 19600. Its totient is φ = 16776.

The previous prime is 18181. The next prime is 18191. The reversal of 18187 is 78181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78181 = 37 ⋅2113.

It is a cyclic number.

It is not a de Polignac number, because 18187 - 2⁷ = 18059 is a prime.

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

It is a Duffinian number.

18187 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (18181) 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, 687 + ... + 712.

It is an arithmetic number, because the mean of its divisors is an integer number (4900).

2¹⁸¹⁸⁷ is an apocalyptic number.

18187 is a deficient number, since it is larger than the sum of its proper divisors (1413).

18187 is a wasteful number, since it uses less digits than its factorization.

18187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1412.

The product of its digits is 448, while the sum is 25.

The square root of 18187 is about 134.8591858199. The cubic root of 18187 is about 26.2978567651.

The spelling of 18187 in words is "eighteen thousand, one hundred eighty-seven".