21011133313217 has 2 divisors, whose sum is σ = 21011133313218. Its totient is φ = 21011133313216.

The previous prime is 21011133313213. The next prime is 21011133313229. The reversal of 21011133313217 is 71231333111012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10592414650801 + 10418718662416 = 3254599^2 + 3227804^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011133313217 - 2² = 21011133313213 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21011133313217.

It is not a weakly prime, because it can be changed into another prime (21011133313213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505566656608 + 10505566656609.

It is an arithmetic number, because the mean of its divisors is an integer number (10505566656609).

Almost surely, 2^{21011133313217} is an apocalyptic number.

It is an amenable number.

21011133313217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011133313217 is an equidigital number, since it uses as much as digits as its factorization.

21011133313217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 29.

Adding to 21011133313217 its reverse (71231333111012), we get a palindrome (92242466424229).

The spelling of 21011133313217 in words is "twenty-one trillion, eleven billion, one hundred thirty-three million, three hundred thirteen thousand, two hundred seventeen".