25856 has 18 divisors (see below), whose sum is σ = 52122. Its totient is φ = 12800.

The previous prime is 25849. The next prime is 25867. The reversal of 25856 is 65852.

It can be written as a sum of positive squares in only one way, i.e., 25600 + 256 = 160^2 + 16^2 .

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

It is a nialpdrome in base 16.

It is a congruent number.

It is an unprimeable number.

25856 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 as a sum of consecutive naturals, namely, 206 + ... + 306.

2²⁵⁸⁵⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26061).

25856 is an abundant number, since it is smaller than the sum of its proper divisors (26266).

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

25856 is an equidigital number, since it uses as much as digits as its factorization.

25856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117 (or 103 counting only the distinct ones).

The product of its digits is 2400, while the sum is 26.

The square root of 25856 is about 160.7980099379. The cubic root of 25856 is about 29.5701671669.

The spelling of 25856 in words is "twenty-five thousand, eight hundred fifty-six".