211221211120217 has 2 divisors, whose sum is σ = 211221211120218. Its totient is φ = 211221211120216.

The previous prime is 211221211120109. The next prime is 211221211120219. The reversal of 211221211120217 is 712021112122112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138800702639641 + 72420508480576 = 11781371^2 + 8510024^2 .

It is a cyclic number.

It is not a de Polignac number, because 211221211120217 - 2¹⁶ = 211221211054681 is a prime.

It is a super-2 number, since 2×211221211120217² (a number of 29 digits) contains 22 as substring.

Together with 211221211120219, 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 (211221211120219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105610605560108 + 105610605560109.

It is an arithmetic number, because the mean of its divisors is an integer number (105610605560109).

Almost surely, 2^{211221211120217} is an apocalyptic number.

It is an amenable number.

211221211120217 is a deficient number, since it is larger than the sum of its proper divisors (1).

211221211120217 is an equidigital number, since it uses as much as digits as its factorization.

211221211120217 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 26.

Adding to 211221211120217 its reverse (712021112122112), we get a palindrome (923242323242329).

The spelling of 211221211120217 in words is "two hundred eleven trillion, two hundred twenty-one billion, two hundred eleven million, one hundred twenty thousand, two hundred seventeen".