20181823 has 2 divisors, whose sum is σ = 20181824. Its totient is φ = 20181822.

The previous prime is 20181809. The next prime is 20181851. The reversal of 20181823 is 32818102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20181823 - 2⁹ = 20181311 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20181803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10090911 + 10090912.

It is an arithmetic number, because the mean of its divisors is an integer number (10090912).

Almost surely, 2^20181823 is an apocalyptic number.

20181823 is a deficient number, since it is larger than the sum of its proper divisors (1).

20181823 is an equidigital number, since it uses as much as digits as its factorization.

20181823 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 20181823 is about 4492.4183910228. The cubic root of 20181823 is about 272.2618540537.

Adding to 20181823 its reverse (32818102), we get a palindrome (52999925).

The spelling of 20181823 in words is "twenty million, one hundred eighty-one thousand, eight hundred twenty-three".