809055991 has 2 divisors, whose sum is σ = 809055992. Its totient is φ = 809055990.

The previous prime is 809055941. The next prime is 809056057. The reversal of 809055991 is 199550908.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-809055991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809055901) 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, 404527995 + 404527996.

It is an arithmetic number, because the mean of its divisors is an integer number (404527996).

Almost surely, 2^809055991 is an apocalyptic number.

809055991 is a deficient number, since it is larger than the sum of its proper divisors (1).

809055991 is an equidigital number, since it uses as much as digits as its factorization.

809055991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 145800, while the sum is 46.

The square root of 809055991 is about 28443.9095589900. The cubic root of 809055991 is about 931.8074807117.

The spelling of 809055991 in words is "eight hundred nine million, fifty-five thousand, nine hundred ninety-one".