21112110221 has 4 divisors (see below), whose sum is σ = 21114252444. Its totient is φ = 21109968000.

The previous prime is 21112110211. The next prime is 21112110247. The reversal of 21112110221 is 12201121112.

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 19464156196 + 1647954025 = 139514^2 + 40595^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112110221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112110196 and 21112110205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112110211) 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, 1056260 + ... + 1076061.

It is an arithmetic number, because the mean of its divisors is an integer number (5278563111).

Almost surely, 2^21112110221 is an apocalyptic number.

It is an amenable number.

21112110221 is a deficient number, since it is larger than the sum of its proper divisors (2142223).

21112110221 is an equidigital number, since it uses as much as digits as its factorization.

21112110221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2142222.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21112110221 its reverse (12201121112), we get a palindrome (33313231333).

The spelling of 21112110221 in words is "twenty-one billion, one hundred twelve million, one hundred ten thousand, two hundred twenty-one".