21002110222221 has 12 divisors (see below), whose sum is σ = 30352578136348. Its totient is φ = 13993931412864.

The previous prime is 21002110222211. The next prime is 21002110222241. The reversal of 21002110222221 is 12222201120012.

It is a happy number.

21002110222221 is a `hidden beast` number, since 2 + 10 + 0 + 211 + 0 + 222 + 221 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 969951189321 + 20032159032900 = 984861^2 + 4475730^2 .

It is not a de Polignac number, because 21002110222221 - 2⁴¹ = 18803086966669 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002110222194 and 21002110222203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002110222211) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 622932370 + ... + 622966083.

Almost surely, 2^{21002110222221} is an apocalyptic number.

It is an amenable number.

21002110222221 is a deficient number, since it is larger than the sum of its proper divisors (9350467914127).

21002110222221 is a wasteful number, since it uses less digits than its factorization.

21002110222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1245900332 (or 1245900329 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21002110222221 its reverse (12222201120012), we get a palindrome (33224311342233).

The spelling of 21002110222221 in words is "twenty-one trillion, two billion, one hundred ten million, two hundred twenty-two thousand, two hundred twenty-one".