25409 has 2 divisors, whose sum is σ = 25410. Its totient is φ = 25408.

The previous prime is 25391. The next prime is 25411. The reversal of 25409 is 90452.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16384 + 9025 = 128^2 + 95^2 .

It is a cyclic number.

It is not a de Polignac number, because 25409 - 2⁸ = 25153 is a prime.

Together with 25411, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12704 + 12705.

It is an arithmetic number, because the mean of its divisors is an integer number (12705).

2²⁵⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

25409 is a deficient number, since it is larger than the sum of its proper divisors (1).

25409 is an equidigital number, since it uses as much as digits as its factorization.

25409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 25409 is about 159.4020075156. The cubic root of 25409 is about 29.3987720653.

It can be divided in two parts, 25 and 409, that added together give a palindrome (434).

The spelling of 25409 in words is "twenty-five thousand, four hundred nine".