25818 has 16 divisors (see below), whose sum is σ = 55776. Its totient is φ = 7920.

The previous prime is 25801. The next prime is 25819. The reversal of 25818 is 81852.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (25819) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88 + ... + 243.

It is an arithmetic number, because the mean of its divisors is an integer number (3486).

2²⁵⁸¹⁸ is an apocalyptic number.

25818 is an abundant number, since it is smaller than the sum of its proper divisors (29958).

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 (27888).

25818 is a wasteful number, since it uses less digits than its factorization.

25818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349.

The product of its digits is 640, while the sum is 24.

The square root of 25818 is about 160.6798058251. The cubic root of 25818 is about 29.5556738542. Note that the first 3 decimals are identical.

It can be divided in two parts, 258 and 18, that added together give a triangular number (276 = T₂₃).

The spelling of 25818 in words is "twenty-five thousand, eight hundred eighteen".