21112121113217 has 2 divisors, whose sum is σ = 21112121113218. Its totient is φ = 21112121113216.

The previous prime is 21112121113183. The next prime is 21112121113243. The reversal of 21112121113217 is 71231112121112.

It is a happy number.

It is an a-pointer prime, because the next prime (21112121113243) can be obtained adding 21112121113217 to its sum of digits (26).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15247470849601 + 5864650263616 = 3904801^2 + 2421704^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112121113217 is a prime.

It is not a weakly prime, because it can be changed into another prime (21112121113277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556060556608 + 10556060556609.

It is an arithmetic number, because the mean of its divisors is an integer number (10556060556609).

Almost surely, 2^{21112121113217} is an apocalyptic number.

It is an amenable number.

21112121113217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112121113217 is an equidigital number, since it uses as much as digits as its factorization.

21112121113217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 336, while the sum is 26.

Adding to 21112121113217 its reverse (71231112121112), we get a palindrome (92343233234329).

The spelling of 21112121113217 in words is "twenty-one trillion, one hundred twelve billion, one hundred twenty-one million, one hundred thirteen thousand, two hundred seventeen".