21221210110221 has 16 divisors (see below), whose sum is σ = 34296905229120. Its totient is φ = 12861339460560.

The previous prime is 21221210110211. The next prime is 21221210110223. The reversal of 21221210110221 is 12201101212212.

21221210110221 is a `hidden beast` number, since 2 + 1 + 221 + 210 + 1 + 10 + 221 = 666.

It is not a de Polignac number, because 21221210110221 - 2²¹ = 21221208013069 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21221210110194 and 21221210110203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221210110223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35725942650 + ... + 35725943243.

It is an arithmetic number, because the mean of its divisors is an integer number (2143556576820).

Almost surely, 2^{21221210110221} is an apocalyptic number.

It is an amenable number.

21221210110221 is a deficient number, since it is larger than the sum of its proper divisors (13075695118899).

21221210110221 is a wasteful number, since it uses less digits than its factorization.

21221210110221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71451885913 (or 71451885907 counting only the distinct ones).

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

Adding to 21221210110221 its reverse (12201101212212), we get a palindrome (33422311322433).

The spelling of 21221210110221 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred ten million, one hundred ten thousand, two hundred twenty-one".