25820 has 12 divisors (see below), whose sum is σ = 54264. Its totient is φ = 10320.

The previous prime is 25819. The next prime is 25841. The reversal of 25820 is 2852.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 626 + ... + 665.

It is an arithmetic number, because the mean of its divisors is an integer number (4522).

2²⁵⁸²⁰ is an apocalyptic number.

25820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25820 is an abundant number, since it is smaller than the sum of its proper divisors (28444).

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 (27132).

25820 is a wasteful number, since it uses less digits than its factorization.

25820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1300 (or 1298 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 25820 is about 160.6860292620. The cubic root of 25820 is about 29.5564370145.

The spelling of 25820 in words is "twenty-five thousand, eight hundred twenty".