25956509 has 4 divisors (see below), whose sum is σ = 25966716. Its totient is φ = 25946304.

The previous prime is 25956503. The next prime is 25956529. The reversal of 25956509 is 90565952.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 22534009 + 3422500 = 4747^2 + 1850^2 .

It is a cyclic number.

It is not a de Polignac number, because 25956509 - 2⁴ = 25956493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25956503) 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, 2117 + ... + 7509.

It is an arithmetic number, because the mean of its divisors is an integer number (6491679).

Almost surely, 2^25956509 is an apocalyptic number.

It is an amenable number.

25956509 is a deficient number, since it is larger than the sum of its proper divisors (10207).

25956509 is an equidigital number, since it uses as much as digits as its factorization.

25956509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10206.

The product of its (nonzero) digits is 121500, while the sum is 41.

The square root of 25956509 is about 5094.7530852829. The cubic root of 25956509 is about 296.0843327092.

The spelling of 25956509 in words is "twenty-five million, nine hundred fifty-six thousand, five hundred nine".