811091 has 4 divisors (see below), whose sum is σ = 853800. Its totient is φ = 768384.

The previous prime is 811081. The next prime is 811099. The reversal of 811091 is 190118.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-811091 is a prime.

It is a super-2 number, since 2×811091² = 1315737220562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (811099) 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, 21326 + ... + 21363.

It is an arithmetic number, because the mean of its divisors is an integer number (213450).

2⁸¹¹⁰⁹¹ is an apocalyptic number.

811091 is a deficient number, since it is larger than the sum of its proper divisors (42709).

811091 is a wasteful number, since it uses less digits than its factorization.

811091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42708.

The product of its (nonzero) digits is 72, while the sum is 20.

The square root of 811091 is about 900.6059071536. The cubic root of 811091 is about 93.2588081390.

The spelling of 811091 in words is "eight hundred eleven thousand, ninety-one".