21222053636221 has 8 divisors (see below), whose sum is σ = 21234827668824. Its totient is φ = 21209281300800.

The previous prime is 21222053636219. The next prime is 21222053636227. The reversal of 21222053636221 is 12263635022212.

It can be written as a sum of positive squares in 4 ways, for example, as 936803308996 + 20285250327225 = 967886^2 + 4503915^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21222053636221 - 2¹ = 21222053636219 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 (21222053636227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25051051 + ... + 25884343.

It is an arithmetic number, because the mean of its divisors is an integer number (2654353458603).

Almost surely, 2^{21222053636221} is an apocalyptic number.

It is an amenable number.

21222053636221 is a deficient number, since it is larger than the sum of its proper divisors (12774032603).

21222053636221 is a wasteful number, since it uses less digits than its factorization.

21222053636221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 848591.

The product of its (nonzero) digits is 103680, while the sum is 37.

Adding to 21222053636221 its reverse (12263635022212), we get a palindrome (33485688658433).

The spelling of 21222053636221 in words is "twenty-one trillion, two hundred twenty-two billion, fifty-three million, six hundred thirty-six thousand, two hundred twenty-one".