809869 has 2 divisors, whose sum is σ = 809870. Its totient is φ = 809868.

The previous prime is 809843. The next prime is 809891. The reversal of 809869 is 968908.

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., 544644 + 265225 = 738^2 + 515^2 .

It is a cyclic number.

It is not a de Polignac number, because 809869 - 2⁷ = 809741 is a prime.

It is a super-2 number, since 2×809869² = 1311775594322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404934 + 404935.

It is an arithmetic number, because the mean of its divisors is an integer number (404935).

2⁸⁰⁹⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

809869 is a deficient number, since it is larger than the sum of its proper divisors (1).

809869 is an equidigital number, since it uses as much as digits as its factorization.

809869 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 809869 is about 899.9272192794. The cubic root of 809869 is about 93.2119496304.

The spelling of 809869 in words is "eight hundred nine thousand, eight hundred sixty-nine".