21221110112221 has 4 divisors (see below), whose sum is σ = 21221257031392. Its totient is φ = 21220963193052.

The previous prime is 21221110112219. The next prime is 21221110112261. The reversal of 21221110112221 is 12221101112212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21221110112221 - 2¹ = 21221110112219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221110112201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73242711 + ... + 73531876.

It is an arithmetic number, because the mean of its divisors is an integer number (5305314257848).

Almost surely, 2^{21221110112221} is an apocalyptic number.

It is an amenable number.

21221110112221 is a deficient number, since it is larger than the sum of its proper divisors (146919171).

21221110112221 is a wasteful number, since it uses less digits than its factorization.

21221110112221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146919170.

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

Adding to 21221110112221 its reverse (12221101112212), we get a palindrome (33442211224433).

Subtracting from 21221110112221 its reverse (12221101112212), we obtain a palindrome (9000009000009).

The spelling of 21221110112221 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred ten million, one hundred twelve thousand, two hundred twenty-one".