809243957 has 2 divisors, whose sum is σ = 809243958. Its totient is φ = 809243956.

The previous prime is 809243947. The next prime is 809243959. The reversal of 809243957 is 759342908.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 807071281 + 2172676 = 28409^2 + 1474^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-809243957 is a prime.

Together with 809243959, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809243959) 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, 404621978 + 404621979.

It is an arithmetic number, because the mean of its divisors is an integer number (404621979).

Almost surely, 2^809243957 is an apocalyptic number.

It is an amenable number.

809243957 is a deficient number, since it is larger than the sum of its proper divisors (1).

809243957 is an equidigital number, since it uses as much as digits as its factorization.

809243957 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 544320, while the sum is 47.

The square root of 809243957 is about 28447.2135190778. The cubic root of 809243957 is about 931.8796366418.

The spelling of 809243957 in words is "eight hundred nine million, two hundred forty-three thousand, nine hundred fifty-seven".