21021221002221 has 40 divisors (see below), whose sum is σ = 34393286255328. Its totient is φ = 12689376300000.

The previous prime is 21021221002157. The next prime is 21021221002237. The reversal of 21021221002221 is 12220012212012.

It is a happy number.

21021221002221 is a `hidden beast` number, since 21 + 0 + 212 + 210 + 0 + 2 + 221 = 666.

It is not a de Polignac number, because 21021221002221 - 2⁶ = 21021221002157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21021221002194 and 21021221002203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021221002261) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 46774050 + ... + 47221331.

Almost surely, 2^{21021221002221} is an apocalyptic number.

It is an amenable number.

21021221002221 is a deficient number, since it is larger than the sum of its proper divisors (13372065253107).

21021221002221 is a wasteful number, since it uses less digits than its factorization.

21021221002221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93995655 (or 93995646 counting only the distinct ones).

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

Adding to 21021221002221 its reverse (12220012212012), we get a palindrome (33241233214233).

The spelling of 21021221002221 in words is "twenty-one trillion, twenty-one billion, two hundred twenty-one million, two thousand, two hundred twenty-one".