808919809 has 2 divisors, whose sum is σ = 808919810. Its totient is φ = 808919808.

The previous prime is 808919779. The next prime is 808919819. The reversal of 808919809 is 908919808.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 435348225 + 373571584 = 20865^2 + 19328^2 .

It is a cyclic number.

It is not a de Polignac number, because 808919809 - 2⁷ = 808919681 is a prime.

It is not a weakly prime, because it can be changed into another prime (808919819) 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, 404459904 + 404459905.

It is an arithmetic number, because the mean of its divisors is an integer number (404459905).

Almost surely, 2^808919809 is an apocalyptic number.

It is an amenable number.

808919809 is a deficient number, since it is larger than the sum of its proper divisors (1).

808919809 is an equidigital number, since it uses as much as digits as its factorization.

808919809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 373248, while the sum is 52.

The square root of 808919809 is about 28441.5155890118. The cubic root of 808919809 is about 931.7551965154.

Subtracting 808919809 from its reverse (908919808), we obtain a palindrome (99999999).

The spelling of 808919809 in words is "eight hundred eight million, nine hundred nineteen thousand, eight hundred nine".