25909 has 4 divisors (see below), whose sum is σ = 27916. Its totient is φ = 23904.

The previous prime is 25903. The next prime is 25913. The reversal of 25909 is 90952.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11025 + 14884 = 105^2 + 122^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25909 is a prime.

It is a Duffinian number.

25909 is a lucky number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25903) 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, 984 + ... + 1009.

It is an arithmetic number, because the mean of its divisors is an integer number (6979).

2²⁵⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

25909 is a deficient number, since it is larger than the sum of its proper divisors (2007).

25909 is a wasteful number, since it uses less digits than its factorization.

25909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2006.

The product of its (nonzero) digits is 810, while the sum is 25.

The square root of 25909 is about 160.9627286051. The cubic root of 25909 is about 29.5903578285.

The spelling of 25909 in words is "twenty-five thousand, nine hundred nine".