221210212100221 has 2 divisors, whose sum is σ = 221210212100222. Its totient is φ = 221210212100220.

The previous prime is 221210212100201. The next prime is 221210212100231. The reversal of 221210212100221 is 122001212012122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 220983387560100 + 226824540121 = 14865510^2 + 476261^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221210212100221 is a prime.

It is a super-2 number, since 2×221210212100221² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221210212100201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110605106050110 + 110605106050111.

It is an arithmetic number, because the mean of its divisors is an integer number (110605106050111).

Almost surely, 2^{221210212100221} is an apocalyptic number.

It is an amenable number.

221210212100221 is a deficient number, since it is larger than the sum of its proper divisors (1).

221210212100221 is an equidigital number, since it uses as much as digits as its factorization.

221210212100221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 221210212100221 its reverse (122001212012122), we get a palindrome (343211424112343).

The spelling of 221210212100221 in words is "two hundred twenty-one trillion, two hundred ten billion, two hundred twelve million, one hundred thousand, two hundred twenty-one".