25581609 has 16 divisors (see below), whose sum is σ = 38420800. Its totient is φ = 16819488.

The previous prime is 25581607. The next prime is 25581613. The reversal of 25581609 is 90618552.

It is a happy number.

It is not a de Polignac number, because 25581609 - 2¹ = 25581607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25581601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4519 + ... + 8460.

It is an arithmetic number, because the mean of its divisors is an integer number (2401300).

Almost surely, 2^25581609 is an apocalyptic number.

It is an amenable number.

25581609 is a deficient number, since it is larger than the sum of its proper divisors (12839191).

25581609 is a wasteful number, since it uses less digits than its factorization.

25581609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13061 (or 13055 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 25581609 is about 5057.8265094801. The cubic root of 25581609 is about 294.6519269180.

The spelling of 25581609 in words is "twenty-five million, five hundred eighty-one thousand, six hundred nine".