25866 has 16 divisors (see below), whose sum is σ = 57600. Its totient is φ = 8604.

The previous prime is 25849. The next prime is 25867. The reversal of 25866 is 66852.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 25866.

It is not an unprimeable number, because it can be changed into a prime (25867) by changing a digit.

25866 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 186 + ... + 293.

It is an arithmetic number, because the mean of its divisors is an integer number (3600).

2²⁵⁸⁶⁶ is an apocalyptic number.

25866 is an abundant number, since it is smaller than the sum of its proper divisors (31734).

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 (28800).

25866 is a wasteful number, since it uses less digits than its factorization.

25866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490 (or 484 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 25866 is about 160.8291018442. The cubic root of 25866 is about 29.5739788361.

It can be divided in two parts, 258 and 66, that added together give a square (324 = 18²).

The spelling of 25866 in words is "twenty-five thousand, eight hundred sixty-six".