811909 has 4 divisors (see below), whose sum is σ = 927904. Its totient is φ = 695916.

The previous prime is 811897. The next prime is 811919. The reversal of 811909 is 909118.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 811909 - 2¹³ = 803717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57987 + ... + 58000.

It is an arithmetic number, because the mean of its divisors is an integer number (231976).

2⁸¹¹⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

811909 is a deficient number, since it is larger than the sum of its proper divisors (115995).

811909 is a wasteful number, since it uses less digits than its factorization.

811909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115994.

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

The square root of 811909 is about 901.0599314141. The cubic root of 811909 is about 93.2901486726.

The spelling of 811909 in words is "eight hundred eleven thousand, nine hundred nine".