21020202212117 has 2 divisors, whose sum is σ = 21020202212118. Its totient is φ = 21020202212116.

The previous prime is 21020202212083. The next prime is 21020202212171. The reversal of 21020202212117 is 71121220202012.

Together with next prime (21020202212171) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17530307460241 + 3489894751876 = 4186921^2 + 1868126^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020202212117 - 2³⁰ = 21019128470293 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21020202212092 and 21020202212101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21020207212117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510101106058 + 10510101106059.

It is an arithmetic number, because the mean of its divisors is an integer number (10510101106059).

Almost surely, 2^{21020202212117} is an apocalyptic number.

It is an amenable number.

21020202212117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020202212117 is an equidigital number, since it uses as much as digits as its factorization.

21020202212117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 23.

Adding to 21020202212117 its reverse (71121220202012), we get a palindrome (92141422414129).

The spelling of 21020202212117 in words is "twenty-one trillion, twenty billion, two hundred two million, two hundred twelve thousand, one hundred seventeen".