21111123223 has 4 divisors (see below), whose sum is σ = 21154473040. Its totient is φ = 21067773408.

The previous prime is 21111123203. The next prime is 21111123227. The reversal of 21111123223 is 32232111112.

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 21111123223 - 2²⁵ = 21077568791 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21111123223.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111123227) 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 in 3 ways as a sum of consecutive naturals, for example, 21674178 + ... + 21675151.

It is an arithmetic number, because the mean of its divisors is an integer number (5288618260).

Almost surely, 2^21111123223 is an apocalyptic number.

21111123223 is a deficient number, since it is larger than the sum of its proper divisors (43349817).

21111123223 is an equidigital number, since it uses as much as digits as its factorization.

21111123223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43349816.

The product of its digits is 144, while the sum is 19.

Adding to 21111123223 its reverse (32232111112), we get a palindrome (53343234335).

The spelling of 21111123223 in words is "twenty-one billion, one hundred eleven million, one hundred twenty-three thousand, two hundred twenty-three".