21112211102221 has 4 divisors (see below), whose sum is σ = 21113428593244. Its totient is φ = 21110993611200.

The previous prime is 21112211102123. The next prime is 21112211102243. The reversal of 21112211102221 is 12220111221112.

It is a happy number.

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 16088722655625 + 5023488446596 = 4011075^2 + 2241314^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112211102221 - 2¹⁷ = 21112210971149 is a prime.

It is a super-2 number, since 2×21112211102221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112211102321) 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, 608719500 + ... + 608754181.

It is an arithmetic number, because the mean of its divisors is an integer number (5278357148311).

Almost surely, 2^{21112211102221} is an apocalyptic number.

It is an amenable number.

21112211102221 is a deficient number, since it is larger than the sum of its proper divisors (1217491023).

21112211102221 is a wasteful number, since it uses less digits than its factorization.

21112211102221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1217491022.

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

Adding to 21112211102221 its reverse (12220111221112), we get a palindrome (33332322323333).

The spelling of 21112211102221 in words is "twenty-one trillion, one hundred twelve billion, two hundred eleven million, one hundred two thousand, two hundred twenty-one".