25218 has 16 divisors (see below), whose sum is σ = 56160. Its totient is φ = 8388.

The previous prime is 25189. The next prime is 25219. The reversal of 25218 is 81252.

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

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

It is a plaindrome in base 7.

It is a self number, because there is not a number n which added to its sum of digits gives 25218.

It is not an unprimeable number, because it can be changed into a prime (25219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180 + ... + 287.

It is an arithmetic number, because the mean of its divisors is an integer number (3510).

2²⁵²¹⁸ is an apocalyptic number.

25218 is an abundant number, since it is smaller than the sum of its proper divisors (30942).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28080).

25218 is a wasteful number, since it uses less digits than its factorization.

25218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478 (or 472 counting only the distinct ones).

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

The square root of 25218 is about 158.8017632144. The cubic root of 25218 is about 29.3249229791.

Subtracting from 25218 its sum of digits (18), we obtain a triangular number (25200 = T₂₂₄).

It can be divided in two parts, 25 and 218, that added together give a 5-th power (243 = 3⁵).

The spelling of 25218 in words is "twenty-five thousand, two hundred eighteen".