18215 has 4 divisors (see below), whose sum is σ = 21864. Its totient is φ = 14568.

The previous prime is 18211. The next prime is 18217. The reversal of 18215 is 51281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51281 = 19 ⋅2699.

It is a cyclic number.

It is not a de Polignac number, because 18215 - 2² = 18211 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18193 and 18202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18211) 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, 1817 + ... + 1826.

It is an arithmetic number, because the mean of its divisors is an integer number (5466).

2¹⁸²¹⁵ is an apocalyptic number.

18215 is a deficient number, since it is larger than the sum of its proper divisors (3649).

18215 is an equidigital number, since it uses as much as digits as its factorization.

18215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3648.

The product of its digits is 80, while the sum is 17.

The square root of 18215 is about 134.9629578810. The cubic root of 18215 is about 26.3113455654.

Adding to 18215 its reverse (51281), we get a palindrome (69496).

The spelling of 18215 in words is "eighteen thousand, two hundred fifteen".