21220112212221 has 16 divisors (see below), whose sum is σ = 30469987353344. Its totient is φ = 13058495175744.

The previous prime is 21220112212219. The next prime is 21220112212223. The reversal of 21220112212221 is 12221221102212.

It is an interprime number because it is at equal distance from previous prime (21220112212219) and next prime (21220112212223).

It is not a de Polignac number, because 21220112212221 - 2¹ = 21220112212219 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220112212223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27716655 + ... + 28471971.

It is an arithmetic number, because the mean of its divisors is an integer number (1904374209584).

Almost surely, 2^{21220112212221} is an apocalyptic number.

It is an amenable number.

21220112212221 is a deficient number, since it is larger than the sum of its proper divisors (9249875141123).

21220112212221 is a wasteful number, since it uses less digits than its factorization.

21220112212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1475700.

The product of its (nonzero) digits is 256, while the sum is 21.

Adding to 21220112212221 its reverse (12221221102212), we get a palindrome (33441333314433).

The spelling of 21220112212221 in words is "twenty-one trillion, two hundred twenty billion, one hundred twelve million, two hundred twelve thousand, two hundred twenty-one".