21212100017 has 2 divisors, whose sum is σ = 21212100018. Its totient is φ = 21212100016.

The previous prime is 21212100001. The next prime is 21212100031. The reversal of 21212100017 is 71000121212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12519148321 + 8692951696 = 111889^2 + 93236^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212100017 - 2⁴ = 21212100001 is a prime.

It is a super-3 number, since 3×21212100017³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 21212099968 and 21212100004.

It is not a weakly prime, because it can be changed into another prime (21212100097) 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, 10606050008 + 10606050009.

It is an arithmetic number, because the mean of its divisors is an integer number (10606050009).

Almost surely, 2^21212100017 is an apocalyptic number.

It is an amenable number.

21212100017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212100017 is an equidigital number, since it uses as much as digits as its factorization.

21212100017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56, while the sum is 17.

Adding to 21212100017 its reverse (71000121212), we get a palindrome (92212221229).

The spelling of 21212100017 in words is "twenty-one billion, two hundred twelve million, one hundred thousand, seventeen".