25689 has 4 divisors (see below), whose sum is σ = 34256. Its totient is φ = 17124.

The previous prime is 25679. The next prime is 25693. The reversal of 25689 is 98652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 25689 - 2⁴ = 25673 is a prime.

It is a D-number.

It is a Duffinian number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (25609) 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, 4279 + ... + 4284.

It is an arithmetic number, because the mean of its divisors is an integer number (8564).

2²⁵⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

25689 is a deficient number, since it is larger than the sum of its proper divisors (8567).

25689 is an equidigital number, since it uses as much as digits as its factorization.

25689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8566.

The product of its digits is 4320, while the sum is 30.

The square root of 25689 is about 160.2778836895. The cubic root of 25689 is about 29.5063665279.

The spelling of 25689 in words is "twenty-five thousand, six hundred eighty-nine".