21221102222221 has 16 divisors (see below), whose sum is σ = 24570124315200. Its totient is φ = 18276547346640.

The previous prime is 21221102222213. The next prime is 21221102222249. The reversal of 21221102222221 is 12222220112212.

It is not a de Polignac number, because 21221102222221 - 2³ = 21221102222213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221102222192 and 21221102222201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221102222251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 419546506 + ... + 419597083.

It is an arithmetic number, because the mean of its divisors is an integer number (1535632769700).

Almost surely, 2^{21221102222221} is an apocalyptic number.

It is an amenable number.

21221102222221 is a deficient number, since it is larger than the sum of its proper divisors (3349022092979).

21221102222221 is an equidigital number, since it uses as much as digits as its factorization.

21221102222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 839143641 (or 839143619 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

Adding to 21221102222221 its reverse (12222220112212), we get a palindrome (33443322334433).

The spelling of 21221102222221 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred two million, two hundred twenty-two thousand, two hundred twenty-one".