20111823 has 24 divisors (see below), whose sum is σ = 30758000. Its totient is φ = 12628224.

The previous prime is 20111809. The next prime is 20111837. The reversal of 20111823 is 32811102.

It is an interprime number because it is at equal distance from previous prime (20111809) and next prime (20111837).

It is not a de Polignac number, because 20111823 - 2¹⁶ = 20046287 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20111796 and 20111805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111803) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 57453 + ... + 57801.

Almost surely, 2^20111823 is an apocalyptic number.

20111823 is a deficient number, since it is larger than the sum of its proper divisors (10646177).

20111823 is a wasteful number, since it uses less digits than its factorization.

20111823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 711 (or 708 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 20111823 is about 4484.6207197488. The cubic root of 20111823 is about 271.9467122759.

Adding to 20111823 its reverse (32811102), we get a palindrome (52922925).

The spelling of 20111823 in words is "twenty million, one hundred eleven thousand, eight hundred twenty-three".