25709809 has 2 divisors, whose sum is σ = 25709810. Its totient is φ = 25709808.

The previous prime is 25709779. The next prime is 25709813. The reversal of 25709809 is 90890752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25280784 + 429025 = 5028^2 + 655^2 .

It is a cyclic number.

It is not a de Polignac number, because 25709809 - 2⁹ = 25709297 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (25719809) 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 as a sum of consecutive naturals, namely, 12854904 + 12854905.

It is an arithmetic number, because the mean of its divisors is an integer number (12854905).

Almost surely, 2^25709809 is an apocalyptic number.

It is an amenable number.

25709809 is a deficient number, since it is larger than the sum of its proper divisors (1).

25709809 is an equidigital number, since it uses as much as digits as its factorization.

25709809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 45360, while the sum is 40.

The square root of 25709809 is about 5070.4840991763. The cubic root of 25709809 is about 295.1433144499.

The spelling of 25709809 in words is "twenty-five million, seven hundred nine thousand, eight hundred nine".