21211222117 has 2 divisors, whose sum is σ = 21211222118. Its totient is φ = 21211222116.

The previous prime is 21211222103. The next prime is 21211222169. The reversal of 21211222117 is 71122211212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14132692161 + 7078529956 = 118881^2 + 84134^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21211222117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211222217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605611058 + 10605611059.

It is an arithmetic number, because the mean of its divisors is an integer number (10605611059).

Almost surely, 2^21211222117 is an apocalyptic number.

It is an amenable number.

21211222117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211222117 is an equidigital number, since it uses as much as digits as its factorization.

21211222117 is an evil number, because the sum of its binary digits is even.

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

Adding to 21211222117 its reverse (71122211212), we get a palindrome (92333433329).

The spelling of 21211222117 in words is "twenty-one billion, two hundred eleven million, two hundred twenty-two thousand, one hundred seventeen".