21311331120217 has 2 divisors, whose sum is σ = 21311331120218. Its totient is φ = 21311331120216.

The previous prime is 21311331120203. The next prime is 21311331120307. The reversal of 21311331120217 is 71202113311312.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20298457955161 + 1012873165056 = 4505381^2 + 1006416^2 .

It is a cyclic number.

It is not a de Polignac number, because 21311331120217 - 2¹¹ = 21311331118169 is a prime.

It is a super-2 number, since 2×21311331120217² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21311331120917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655665560108 + 10655665560109.

It is an arithmetic number, because the mean of its divisors is an integer number (10655665560109).

Almost surely, 2^{21311331120217} is an apocalyptic number.

It is an amenable number.

21311331120217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311331120217 is an equidigital number, since it uses as much as digits as its factorization.

21311331120217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 28.

Adding to 21311331120217 its reverse (71202113311312), we get a palindrome (92513444431529).

The spelling of 21311331120217 in words is "twenty-one trillion, three hundred eleven billion, three hundred thirty-one million, one hundred twenty thousand, two hundred seventeen".