25831 has 4 divisors (see below), whose sum is σ = 27832. Its totient is φ = 23832.

The previous prime is 25819. The next prime is 25841. The reversal of 25831 is 13852.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 25831 - 2⁵ = 25799 is a prime.

It is a super-2 number, since 2×25831² = 1334481122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 25799 and 25808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25801) 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, 981 + ... + 1006.

It is an arithmetic number, because the mean of its divisors is an integer number (6958).

2²⁵⁸³¹ is an apocalyptic number.

25831 is a deficient number, since it is larger than the sum of its proper divisors (2001).

25831 is a wasteful number, since it uses less digits than its factorization.

25831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2000.

The product of its digits is 240, while the sum is 19.

The square root of 25831 is about 160.7202538574. The cubic root of 25831 is about 29.5606336921.

It can be divided in two parts, 258 and 31, that added together give a square (289 = 17²).

The spelling of 25831 in words is "twenty-five thousand, eight hundred thirty-one".