25845509 has 2 divisors, whose sum is σ = 25845510. Its totient is φ = 25845508.

The previous prime is 25845439. The next prime is 25845551. The reversal of 25845509 is 90554852.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16785409 + 9060100 = 4097^2 + 3010^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25845509 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25845569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12922754 + 12922755.

It is an arithmetic number, because the mean of its divisors is an integer number (12922755).

Almost surely, 2^25845509 is an apocalyptic number.

It is an amenable number.

25845509 is a deficient number, since it is larger than the sum of its proper divisors (1).

25845509 is an equidigital number, since it uses as much as digits as its factorization.

25845509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72000, while the sum is 38.

The square root of 25845509 is about 5083.8478537423. The cubic root of 25845509 is about 295.6616728816.

The spelling of 25845509 in words is "twenty-five million, eight hundred forty-five thousand, five hundred nine".