21321111023 has 4 divisors (see below), whose sum is σ = 21323012640. Its totient is φ = 21319209408.

The previous prime is 21321110957. The next prime is 21321111047. The reversal of 21321111023 is 32011112312.

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 21321111023 - 2²⁴ = 21304333807 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21321110992 and 21321111010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321111073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 933890 + ... + 956447.

It is an arithmetic number, because the mean of its divisors is an integer number (5330753160).

Almost surely, 2^21321111023 is an apocalyptic number.

21321111023 is a deficient number, since it is larger than the sum of its proper divisors (1901617).

21321111023 is a wasteful number, since it uses less digits than its factorization.

21321111023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1901616.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21321111023 its reverse (32011112312), we get a palindrome (53332223335).

The spelling of 21321111023 in words is "twenty-one billion, three hundred twenty-one million, one hundred eleven thousand, twenty-three".