18823 has 4 divisors (see below), whose sum is σ = 21520. Its totient is φ = 16128.

The previous prime is 18803. The next prime is 18839. The reversal of 18823 is 32881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32881 = 131 ⋅251.

It is not a de Polignac number, because 18823 - 2⁹ = 18311 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a nialpdrome in base 12.

It is a junction number, because it is equal to n+sod(n) for n = 18794 and 18803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1338 + ... + 1351.

It is an arithmetic number, because the mean of its divisors is an integer number (5380).

2¹⁸⁸²³ is an apocalyptic number.

18823 is a deficient number, since it is larger than the sum of its proper divisors (2697).

18823 is an equidigital number, since it uses as much as digits as its factorization.

18823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2696.

The product of its digits is 384, while the sum is 22.

The square root of 18823 is about 137.1969387414. The cubic root of 18823 is about 26.6008969490.

It can be divided in two parts, 18 and 823, that added together give a square (841 = 29²).

The spelling of 18823 in words is "eighteen thousand, eight hundred twenty-three".