25644 has 12 divisors (see below), whose sum is σ = 59864. Its totient is φ = 8544.

The previous prime is 25643. The next prime is 25657. The reversal of 25644 is 44652.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×25644² = 1315229472, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 25644.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 25644.

It is not an unprimeable number, because it can be changed into a prime (25643) 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, 1057 + ... + 1080.

2²⁵⁶⁴⁴ is an apocalyptic number.

It is an amenable number.

25644 is an abundant number, since it is smaller than the sum of its proper divisors (34220).

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 (29932).

25644 is a wasteful number, since it uses less digits than its factorization.

25644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2144 (or 2142 counting only the distinct ones).

The product of its digits is 960, while the sum is 21.

The square root of 25644 is about 160.1374409687. The cubic root of 25644 is about 29.4891274689.

It can be divided in two parts, 256 and 44, that added together give a triangular number (300 = T₂₄).

The spelling of 25644 in words is "twenty-five thousand, six hundred forty-four".