2564778509 has 2 divisors, whose sum is σ = 2564778510. Its totient is φ = 2564778508.

The previous prime is 2564778487. The next prime is 2564778539. The reversal of 2564778509 is 9058774652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2560866025 + 3912484 = 50605^2 + 1978^2 .

It is a cyclic number.

It is not a de Polignac number, because 2564778509 - 2²⁰ = 2563729933 is a prime.

It is a super-3 number, since 3×2564778509³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2564778539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1282389254 + 1282389255.

It is an arithmetic number, because the mean of its divisors is an integer number (1282389255).

Almost surely, 2^2564778509 is an apocalyptic number.

It is an amenable number.

2564778509 is a deficient number, since it is larger than the sum of its proper divisors (1).

2564778509 is an equidigital number, since it uses as much as digits as its factorization.

2564778509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4233600, while the sum is 53.

The square root of 2564778509 is about 50643.6423354403. The cubic root of 2564778509 is about 1368.8313882395.

The spelling of 2564778509 in words is "two billion, five hundred sixty-four million, seven hundred seventy-eight thousand, five hundred nine".