21021020210221 has 2 divisors, whose sum is σ = 21021020210222. Its totient is φ = 21021020210220.

The previous prime is 21021020210219. The next prime is 21021020210227. The reversal of 21021020210221 is 12201202012012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20928923134596 + 92097075625 = 4574814^2 + 303475^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021020210221 - 2¹ = 21021020210219 is a prime.

Together with 21021020210219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21021020210195 and 21021020210204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021020210227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510510105110 + 10510510105111.

It is an arithmetic number, because the mean of its divisors is an integer number (10510510105111).

Almost surely, 2^{21021020210221} is an apocalyptic number.

It is an amenable number.

21021020210221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021020210221 is an equidigital number, since it uses as much as digits as its factorization.

21021020210221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21021020210221 its reverse (12201202012012), we get a palindrome (33222222222233).

The spelling of 21021020210221 in words is "twenty-one trillion, twenty-one billion, twenty million, two hundred ten thousand, two hundred twenty-one".