809792561 has 2 divisors, whose sum is σ = 809792562. Its totient is φ = 809792560.

The previous prime is 809792551. The next prime is 809792573. The reversal of 809792561 is 165297908.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 589566961 + 220225600 = 24281^2 + 14840^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-809792561 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (809792531) 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, 404896280 + 404896281.

It is an arithmetic number, because the mean of its divisors is an integer number (404896281).

Almost surely, 2^809792561 is an apocalyptic number.

It is an amenable number.

809792561 is a deficient number, since it is larger than the sum of its proper divisors (1).

809792561 is an equidigital number, since it uses as much as digits as its factorization.

809792561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 272160, while the sum is 47.

The square root of 809792561 is about 28456.8543764064. The cubic root of 809792561 is about 932.0901695349.

The spelling of 809792561 in words is "eight hundred nine million, seven hundred ninety-two thousand, five hundred sixty-one".