21210220102217 has 2 divisors, whose sum is σ = 21210220102218. Its totient is φ = 21210220102216.

The previous prime is 21210220102193. The next prime is 21210220102249. The reversal of 21210220102217 is 71220102201212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11116516212736 + 10093703889481 = 3334144^2 + 3177059^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21210220102217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210220102192 and 21210220102201.

It is not a weakly prime, because it can be changed into another prime (21210220132217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605110051108 + 10605110051109.

It is an arithmetic number, because the mean of its divisors is an integer number (10605110051109).

Almost surely, 2^{21210220102217} is an apocalyptic number.

It is an amenable number.

21210220102217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210220102217 is an equidigital number, since it uses as much as digits as its factorization.

21210220102217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 23.

Adding to 21210220102217 its reverse (71220102201212), we get a palindrome (92430322303429).

The spelling of 21210220102217 in words is "twenty-one trillion, two hundred ten billion, two hundred twenty million, one hundred two thousand, two hundred seventeen".