809839 has 2 divisors, whose sum is σ = 809840. Its totient is φ = 809838.

The previous prime is 809833. The next prime is 809843. The reversal of 809839 is 938908.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 809839 - 2¹⁵ = 777071 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 809798 and 809807.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809833) 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, 404919 + 404920.

It is an arithmetic number, because the mean of its divisors is an integer number (404920).

2⁸⁰⁹⁸³⁹ is an apocalyptic number.

809839 is a deficient number, since it is larger than the sum of its proper divisors (1).

809839 is an equidigital number, since it uses as much as digits as its factorization.

809839 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 809839 is about 899.9105511105. The cubic root of 809839 is about 93.2107986653.

The spelling of 809839 in words is "eight hundred nine thousand, eight hundred thirty-nine".