2565809 has 2 divisors, whose sum is σ = 2565810. Its totient is φ = 2565808.

The previous prime is 2565799. The next prime is 2565847. The reversal of 2565809 is 9085652.

2565809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1682209 + 883600 = 1297^2 + 940^2 .

It is a cyclic number.

It is not a de Polignac number, because 2565809 - 2¹⁶ = 2500273 is a prime.

It is not a weakly prime, because it can be changed into another prime (2565109) 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, 1282904 + 1282905.

It is an arithmetic number, because the mean of its divisors is an integer number (1282905).

2^2565809 is an apocalyptic number.

It is an amenable number.

2565809 is a deficient number, since it is larger than the sum of its proper divisors (1).

2565809 is an equidigital number, since it uses as much as digits as its factorization.

2565809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 35.

The square root of 2565809 is about 1601.8142838669. The cubic root of 2565809 is about 136.9014689260.

The spelling of 2565809 in words is "two million, five hundred sixty-five thousand, eight hundred nine".