21112222111021 has 4 divisors (see below), whose sum is σ = 21112232469372. Its totient is φ = 21112211752672.

The previous prime is 21112222110979. The next prime is 21112222111027. The reversal of 21112222111021 is 12011122221112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 9840053776996 + 11272168334025 = 3136886^2 + 3357405^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112222111021 - 2⁴¹ = 18913198855469 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 21112222111021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112222111027) 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, 995266 + ... + 6573811.

It is an arithmetic number, because the mean of its divisors is an integer number (5278058117343).

Almost surely, 2^{21112222111021} is an apocalyptic number.

It is an amenable number.

21112222111021 is a deficient number, since it is larger than the sum of its proper divisors (10358351).

21112222111021 is an equidigital number, since it uses as much as digits as its factorization.

21112222111021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10358350.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21112222111021 its reverse (12011122221112), we get a palindrome (33123344332133).

The spelling of 21112222111021 in words is "twenty-one trillion, one hundred twelve billion, two hundred twenty-two million, one hundred eleven thousand, twenty-one".