813823 has 4 divisors (see below), whose sum is σ = 815760. Its totient is φ = 811888.

The previous prime is 813817. The next prime is 813829. The reversal of 813823 is 328318.

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

It is an interprime number because it is at equal distance from previous prime (813817) and next prime (813829).

It is a cyclic number.

It is not a de Polignac number, because 813823 - 2⁹ = 813311 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 (813829) 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, 43 + ... + 1276.

It is an arithmetic number, because the mean of its divisors is an integer number (203940).

2⁸¹³⁸²³ is an apocalyptic number.

813823 is a deficient number, since it is larger than the sum of its proper divisors (1937).

813823 is a wasteful number, since it uses less digits than its factorization.

813823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1936.

The product of its digits is 1152, while the sum is 25.

The square root of 813823 is about 902.1213887277. The cubic root of 813823 is about 93.3633987607.

It can be divided in two parts, 8 and 13823, that added together give a palindrome (13831).

The spelling of 813823 in words is "eight hundred thirteen thousand, eight hundred twenty-three".