21111202102221 has 144 divisors (see below), whose sum is σ = 38891253256128. Its totient is φ = 10912019328000.

The previous prime is 21111202102219. The next prime is 21111202102241. The reversal of 21111202102221 is 12220120211112.

21111202102221 is a `hidden beast` number, since 2 + 111 + 120 + 210 + 2 + 221 = 666.

It is not a de Polignac number, because 21111202102221 - 2¹ = 21111202102219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21111202102194 and 21111202102203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111202102241) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 962344965 + ... + 962366901.

It is an arithmetic number, because the mean of its divisors is an integer number (270078147612).

Almost surely, 2^{21111202102221} is an apocalyptic number.

21111202102221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21111202102221 is a deficient number, since it is larger than the sum of its proper divisors (17780051153907).

21111202102221 is a wasteful number, since it uses less digits than its factorization.

21111202102221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22952 (or 22942 counting only the distinct ones).

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

Adding to 21111202102221 its reverse (12220120211112), we get a palindrome (33331322313333).

The spelling of 21111202102221 in words is "twenty-one trillion, one hundred eleven billion, two hundred two million, one hundred two thousand, two hundred twenty-one".