21211101211221 has 24 divisors (see below), whose sum is σ = 33037401983040. Its totient is φ = 13069741435200.

The previous prime is 21211101211217. The next prime is 21211101211229. The reversal of 21211101211221 is 12211210111212.

It is a happy number.

21211101211221 is a `hidden beast` number, since 2 + 121 + 110 + 1 + 211 + 221 = 666.

It is not a de Polignac number, because 21211101211221 - 2² = 21211101211217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21211101211194 and 21211101211203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211101211229) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1512694545 + ... + 1512708566.

It is an arithmetic number, because the mean of its divisors is an integer number (1376558415960).

Almost surely, 2^{21211101211221} is an apocalyptic number.

It is an amenable number.

21211101211221 is a deficient number, since it is larger than the sum of its proper divisors (11826300771819).

21211101211221 is a wasteful number, since it uses less digits than its factorization.

21211101211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3025403177 (or 3025403174 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21211101211221 its reverse (12211210111212), we get a palindrome (33422311322433).

The spelling of 21211101211221 in words is "twenty-one trillion, two hundred eleven billion, one hundred one million, two hundred eleven thousand, two hundred twenty-one".