809811 has 16 divisors (see below), whose sum is σ = 1216800. Its totient is φ = 532224.

The previous prime is 809803. The next prime is 809821. The reversal of 809811 is 118908.

It is not a de Polignac number, because 809811 - 2³ = 809803 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

809811 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (809801) 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 in 15 ways as a sum of consecutive naturals, for example, 2235 + ... + 2571.

It is an arithmetic number, because the mean of its divisors is an integer number (76050).

2⁸⁰⁹⁸¹¹ is an apocalyptic number.

809811 is a deficient number, since it is larger than the sum of its proper divisors (406989).

809811 is a wasteful number, since it uses less digits than its factorization.

809811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435 (or 429 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The square root of 809811 is about 899.8949938743. The cubic root of 809811 is about 93.2097244055.

The spelling of 809811 in words is "eight hundred nine thousand, eight hundred eleven".