22518 has 20 divisors (see below), whose sum is σ = 50820. Its totient is φ = 7452.

The previous prime is 22511. The next prime is 22531. The reversal of 22518 is 81522.

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 22518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22511) by changing a digit.

22518 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 93 + ... + 231.

It is an arithmetic number, because the mean of its divisors is an integer number (2541).

2²²⁵¹⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 22518, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25410).

22518 is an abundant number, since it is smaller than the sum of its proper divisors (28302).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

22518 is a wasteful number, since it uses less digits than its factorization.

22518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153 (or 144 counting only the distinct ones).

The product of its digits is 160, while the sum is 18.

The square root of 22518 is about 150.0599880048. The cubic root of 22518 is about 28.2386071480.

Subtracting from 22518 its sum of digits (18), we obtain a square (22500 = 150²).

It can be divided in two parts, 225 and 18, that added together give a 5-th power (243 = 3⁵).

The spelling of 22518 in words is "twenty-two thousand, five hundred eighteen".