21122112217 has 2 divisors, whose sum is σ = 21122112218. Its totient is φ = 21122112216.

The previous prime is 21122112203. The next prime is 21122112227. The reversal of 21122112217 is 71221122112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19529783001 + 1592329216 = 139749^2 + 39904^2 .

It is a cyclic number.

It is not a de Polignac number, because 21122112217 - 2¹¹ = 21122110169 is a prime.

It is a super-2 number, since 2×21122112217² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21122112227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561056108 + 10561056109.

It is an arithmetic number, because the mean of its divisors is an integer number (10561056109).

Almost surely, 2^21122112217 is an apocalyptic number.

It is an amenable number.

21122112217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122112217 is an equidigital number, since it uses as much as digits as its factorization.

21122112217 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 21122112217 its reverse (71221122112), we get a palindrome (92343234329).

The spelling of 21122112217 in words is "twenty-one billion, one hundred twenty-two million, one hundred twelve thousand, two hundred seventeen".