25664909 has 4 divisors (see below), whose sum is σ = 25741404. Its totient is φ = 25588416.

The previous prime is 25664887. The next prime is 25664923. The reversal of 25664909 is 90946652.

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 5189284 + 20475625 = 2278^2 + 4525^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25664909 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25664929) 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, 37742 + ... + 38415.

It is an arithmetic number, because the mean of its divisors is an integer number (6435351).

Almost surely, 2^25664909 is an apocalyptic number.

It is an amenable number.

25664909 is a deficient number, since it is larger than the sum of its proper divisors (76495).

25664909 is an equidigital number, since it uses as much as digits as its factorization.

25664909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76494.

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 25664909 is about 5066.0545792559. The cubic root of 25664909 is about 294.9714000809.

The spelling of 25664909 in words is "twenty-five million, six hundred sixty-four thousand, nine hundred nine".