21212221117 has 2 divisors, whose sum is σ = 21212221118. Its totient is φ = 21212221116.

The previous prime is 21212221061. The next prime is 21212221133. The reversal of 21212221117 is 71112221212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13081411876 + 8130809241 = 114374^2 + 90171^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212221117 - 2¹⁹ = 21211696829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212221517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606110558 + 10606110559.

It is an arithmetic number, because the mean of its divisors is an integer number (10606110559).

Almost surely, 2^21212221117 is an apocalyptic number.

It is an amenable number.

21212221117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212221117 is an equidigital number, since it uses as much as digits as its factorization.

21212221117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 224, while the sum is 22.

Adding to 21212221117 its reverse (71112221212), we get a palindrome (92324442329).

The spelling of 21212221117 in words is "twenty-one billion, two hundred twelve million, two hundred twenty-one thousand, one hundred seventeen".