21212101102221 has 24 divisors (see below), whose sum is σ = 30813261608376. Its totient is φ = 14061366558720.

The previous prime is 21212101102163. The next prime is 21212101102223. The reversal of 21212101102221 is 12220110121212.

21212101102221 is a `hidden beast` number, since 2 + 121 + 210 + 110 + 2 + 221 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 6166903055625 + 15045198046596 = 2483325^2 + 3878814^2 .

It is not a de Polignac number, because 21212101102221 - 2²² = 21212096907917 is a prime.

It is a super-3 number, since 3×21212101102221³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 21212101102194 and 21212101102203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212101102223) 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, 680551 + ... + 6548843.

It is an arithmetic number, because the mean of its divisors is an integer number (1283885900349).

Almost surely, 2^{21212101102221} is an apocalyptic number.

It is an amenable number.

21212101102221 is a deficient number, since it is larger than the sum of its proper divisors (9601160506155).

21212101102221 is a wasteful number, since it uses less digits than its factorization.

21212101102221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5870573 (or 5870570 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21212101102221 its reverse (12220110121212), we get a palindrome (33432211223433).

The spelling of 21212101102221 in words is "twenty-one trillion, two hundred twelve billion, one hundred one million, one hundred two thousand, two hundred twenty-one".