809911 has 4 divisors (see below), whose sum is σ = 811800. Its totient is φ = 808024.

The previous prime is 809909. The next prime is 809917. The reversal of 809911 is 119908.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 809911 - 2¹ = 809909 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 809911.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809917) 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 in 3 ways as a sum of consecutive naturals, for example, 45 + ... + 1273.

It is an arithmetic number, because the mean of its divisors is an integer number (202950).

2⁸⁰⁹⁹¹¹ is an apocalyptic number.

809911 is a deficient number, since it is larger than the sum of its proper divisors (1889).

809911 is a wasteful number, since it uses less digits than its factorization.

809911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1888.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 809911 is about 899.9505541973. The cubic root of 809911 is about 93.2135609339.

The spelling of 809911 in words is "eight hundred nine thousand, nine hundred eleven".