811823 has 4 divisors (see below), whose sum is σ = 821688. Its totient is φ = 801960.

The previous prime is 811819. The next prime is 811861. The reversal of 811823 is 328118.

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 811823 - 2² = 811819 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811123) 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 3 ways as a sum of consecutive naturals, for example, 4808 + ... + 4973.

It is an arithmetic number, because the mean of its divisors is an integer number (205422).

2⁸¹¹⁸²³ is an apocalyptic number.

811823 is a gapful number since it is divisible by the number (83) formed by its first and last digit.

811823 is a deficient number, since it is larger than the sum of its proper divisors (9865).

811823 is an equidigital number, since it uses as much as digits as its factorization.

811823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9864.

The product of its digits is 384, while the sum is 23.

The square root of 811823 is about 901.0122085743. The cubic root of 811823 is about 93.2868546926.

The spelling of 811823 in words is "eight hundred eleven thousand, eight hundred twenty-three".