21222211222221 has 16 divisors (see below), whose sum is σ = 29960864765568. Its totient is φ = 13315854579200.

The previous prime is 21222211222171. The next prime is 21222211222253. The reversal of 21222211222221 is 12222211222212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21222211222221 - 2²⁹ = 21221674351309 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21222211222191 and 21222211222200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222211222321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25019656 + ... + 25853966.

It is an arithmetic number, because the mean of its divisors is an integer number (1872554047848).

Almost surely, 2^{21222211222221} is an apocalyptic number.

It is an amenable number.

21222211222221 is a deficient number, since it is larger than the sum of its proper divisors (8738653543347).

21222211222221 is a wasteful number, since it uses less digits than its factorization.

21222211222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1333092.

The product of its digits is 1024, while the sum is 24.

Adding to 21222211222221 its reverse (12222211222212), we get a palindrome (33444422444433).

Subtracting from 21222211222221 its reverse (12222211222212), we obtain a palindrome (9000000000009).

The spelling of 21222211222221 in words is "twenty-one trillion, two hundred twenty-two billion, two hundred eleven million, two hundred twenty-two thousand, two hundred twenty-one".