21112022021 has 4 divisors (see below), whose sum is σ = 21321052044. Its totient is φ = 20902992000.

The previous prime is 21112021943. The next prime is 21112022053. The reversal of 21112022021 is 12022021112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19820697796 + 1291324225 = 140786^2 + 35935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112022021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112021987 and 21112022005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112022081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104514860 + ... + 104515061.

It is an arithmetic number, because the mean of its divisors is an integer number (5330263011).

Almost surely, 2^21112022021 is an apocalyptic number.

It is an amenable number.

21112022021 is a deficient number, since it is larger than the sum of its proper divisors (209030023).

21112022021 is a wasteful number, since it uses less digits than its factorization.

21112022021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209030022.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21112022021 its reverse (12022021112), we get a palindrome (33134043133).

Subtracting from 21112022021 its reverse (12022021112), we obtain a palindrome (9090000909).

The spelling of 21112022021 in words is "twenty-one billion, one hundred twelve million, twenty-two thousand, twenty-one".