25609 has 2 divisors, whose sum is σ = 25610. Its totient is φ = 25608.

The previous prime is 25603. The next prime is 25621. The reversal of 25609 is 90652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25600 + 9 = 160^2 + 3^2 .

It is a cyclic number.

It is not a de Polignac number, because 25609 - 2³ = 25601 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 25609.

It is not a weakly prime, because it can be changed into another prime (25601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12804 + 12805.

It is an arithmetic number, because the mean of its divisors is an integer number (12805).

2²⁵⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

25609 is a deficient number, since it is larger than the sum of its proper divisors (1).

25609 is an equidigital number, since it uses as much as digits as its factorization.

25609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 25609 is about 160.0281225285. The cubic root of 25609 is about 29.4757053640.

It can be divided in two parts, 25 and 609, that multiplied together give a triangular number (15225 = T₁₇₄).

The spelling of 25609 in words is "twenty-five thousand, six hundred nine".