21221201222201 has 2 divisors, whose sum is σ = 21221201222202. Its totient is φ = 21221201222200.

The previous prime is 21221201222171. The next prime is 21221201222203. The reversal of 21221201222201 is 10222210212212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16696221382201 + 4524979840000 = 4086101^2 + 2127200^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221201222201 - 2¹⁰ = 21221201221177 is a prime.

Together with 21221201222203, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21221201222203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610600611100 + 10610600611101.

It is an arithmetic number, because the mean of its divisors is an integer number (10610600611101).

Almost surely, 2^{21221201222201} is an apocalyptic number.

It is an amenable number.

21221201222201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221201222201 is an equidigital number, since it uses as much as digits as its factorization.

21221201222201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21221201222201 its reverse (10222210212212), we get a palindrome (31443411434413).

The spelling of 21221201222201 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred twenty-two thousand, two hundred one".