2565642509 has 2 divisors, whose sum is σ = 2565642510. Its totient is φ = 2565642508.

The previous prime is 2565642481. The next prime is 2565642539. The reversal of 2565642509 is 9052465652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2367114409 + 198528100 = 48653^2 + 14090^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2565642509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2565642509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2565642539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1282821254 + 1282821255.

It is an arithmetic number, because the mean of its divisors is an integer number (1282821255).

Almost surely, 2^2565642509 is an apocalyptic number.

It is an amenable number.

2565642509 is a deficient number, since it is larger than the sum of its proper divisors (1).

2565642509 is an equidigital number, since it uses as much as digits as its factorization.

2565642509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648000, while the sum is 44.

The square root of 2565642509 is about 50652.1718093114. The cubic root of 2565642509 is about 1368.9850776046.

The spelling of 2565642509 in words is "two billion, five hundred sixty-five million, six hundred forty-two thousand, five hundred nine".