21211021211221 has 8 divisors (see below), whose sum is σ = 21662782291584. Its totient is φ = 20759279412480.

The previous prime is 21211021211209. The next prime is 21211021211243. The reversal of 21211021211221 is 12211212011212.

It is a happy number.

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 21211021211221 - 2¹¹ = 21211021209173 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 (21211021212221) 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, 2585935 + ... + 7007788.

It is an arithmetic number, because the mean of its divisors is an integer number (2707847786448).

Almost surely, 2^{21211021211221} is an apocalyptic number.

It is an amenable number.

21211021211221 is a deficient number, since it is larger than the sum of its proper divisors (451761080363).

21211021211221 is an equidigital number, since it uses as much as digits as its factorization.

21211021211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9640811.

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

Adding to 21211021211221 its reverse (12211212011212), we get a palindrome (33422233222433).

The spelling of 21211021211221 in words is "twenty-one trillion, two hundred eleven billion, twenty-one million, two hundred eleven thousand, two hundred twenty-one".