21102102121221 has 16 divisors (see below), whose sum is σ = 34104407469120. Its totient is φ = 12789152800560.

The previous prime is 21102102121207. The next prime is 21102102121241. The reversal of 21102102121221 is 12212120120112.

21102102121221 is a `hidden beast` number, since 2 + 110 + 210 + 2 + 121 + 221 = 666.

It is not a de Polignac number, because 21102102121221 - 2²⁷ = 21101967903493 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21102102121194 and 21102102121203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102102121241) 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, 35525424150 + ... + 35525424743.

It is an arithmetic number, because the mean of its divisors is an integer number (2131525466820).

Almost surely, 2^{21102102121221} is an apocalyptic number.

It is an amenable number.

21102102121221 is a deficient number, since it is larger than the sum of its proper divisors (13002305347899).

21102102121221 is a wasteful number, since it uses less digits than its factorization.

21102102121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71050848913 (or 71050848907 counting only the distinct ones).

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

Adding to 21102102121221 its reverse (12212120120112), we get a palindrome (33314222241333).

The spelling of 21102102121221 in words is "twenty-one trillion, one hundred two billion, one hundred two million, one hundred twenty-one thousand, two hundred twenty-one".