809474891 has 2 divisors, whose sum is σ = 809474892. Its totient is φ = 809474890.

The previous prime is 809474801. The next prime is 809474923. The reversal of 809474891 is 198474908.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-809474891 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (809474801) 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, 404737445 + 404737446.

It is an arithmetic number, because the mean of its divisors is an integer number (404737446).

Almost surely, 2^809474891 is an apocalyptic number.

809474891 is a deficient number, since it is larger than the sum of its proper divisors (1).

809474891 is an equidigital number, since it uses as much as digits as its factorization.

809474891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 580608, while the sum is 50.

The square root of 809474891 is about 28451.2722211152. The cubic root of 809474891 is about 931.9682717284.

The spelling of 809474891 in words is "eight hundred nine million, four hundred seventy-four thousand, eight hundred ninety-one".