25609921 has 4 divisors (see below), whose sum is σ = 25655344. Its totient is φ = 25564500.

The previous prime is 25609889. The next prime is 25609949. The reversal of 25609921 is 12990652.

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 a cyclic number.

It is not a de Polignac number, because 25609921 - 2⁵ = 25609889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25609421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21855 + ... + 22996.

It is an arithmetic number, because the mean of its divisors is an integer number (6413836).

Almost surely, 2^25609921 is an apocalyptic number.

It is an amenable number.

25609921 is a deficient number, since it is larger than the sum of its proper divisors (45423).

25609921 is an equidigital number, since it uses as much as digits as its factorization.

25609921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45422.

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 25609921 is about 5060.6245661973. The cubic root of 25609921 is about 294.7605871372.

The spelling of 25609921 in words is "twenty-five million, six hundred nine thousand, nine hundred twenty-one".