809255591 has 2 divisors, whose sum is σ = 809255592. Its totient is φ = 809255590.

The previous prime is 809255563. The next prime is 809255609. The reversal of 809255591 is 195552908.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-809255591 is a prime.

It is a super-2 number, since 2×809255591² = 1309789223129518562, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is equal to p_41597864 and since 809255591 and 41597864 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809255501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404627795 + 404627796.

It is an arithmetic number, because the mean of its divisors is an integer number (404627796).

Almost surely, 2^809255591 is an apocalyptic number.

809255591 is a deficient number, since it is larger than the sum of its proper divisors (1).

809255591 is an equidigital number, since it uses as much as digits as its factorization.

809255591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162000, while the sum is 44.

The square root of 809255591 is about 28447.4180023425. The cubic root of 809255591 is about 931.8841023062.

The spelling of 809255591 in words is "eight hundred nine million, two hundred fifty-five thousand, five hundred ninety-one".