21102220221217 has 2 divisors, whose sum is σ = 21102220221218. Its totient is φ = 21102220221216.

The previous prime is 21102220221197. The next prime is 21102220221227. The reversal of 21102220221217 is 71212202220112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21027690675216 + 74529546001 = 4585596^2 + 273001^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102220221217 - 2¹¹ = 21102220219169 is a prime.

It is a super-2 number, since 2×21102220221217² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21102220221191 and 21102220221200.

It is not a weakly prime, because it can be changed into another prime (21102220221227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551110110608 + 10551110110609.

It is an arithmetic number, because the mean of its divisors is an integer number (10551110110609).

Almost surely, 2^{21102220221217} is an apocalyptic number.

It is an amenable number.

21102220221217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102220221217 is an equidigital number, since it uses as much as digits as its factorization.

21102220221217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 896, while the sum is 25.

Adding to 21102220221217 its reverse (71212202220112), we get a palindrome (92314422441329).

The spelling of 21102220221217 in words is "twenty-one trillion, one hundred two billion, two hundred twenty million, two hundred twenty-one thousand, two hundred seventeen".