25891 has 4 divisors (see below), whose sum is σ = 27432. Its totient is φ = 24352.

The previous prime is 25889. The next prime is 25903. The reversal of 25891 is 19852.

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 25891 - 2¹ = 25889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 745 + ... + 778.

It is an arithmetic number, because the mean of its divisors is an integer number (6858).

2²⁵⁸⁹¹ is an apocalyptic number.

25891 is a deficient number, since it is larger than the sum of its proper divisors (1541).

25891 is a wasteful number, since it uses less digits than its factorization.

25891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540.

The product of its digits is 720, while the sum is 25.

The square root of 25891 is about 160.9068053253. The cubic root of 25891 is about 29.5835037130.

The spelling of 25891 in words is "twenty-five thousand, eight hundred ninety-one".