21210201217 has 2 divisors, whose sum is σ = 21210201218. Its totient is φ = 21210201216.

The previous prime is 21210201179. The next prime is 21210201241. The reversal of 21210201217 is 71210201212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11833958656 + 9376242561 = 108784^2 + 96831^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21210201217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210201194 and 21210201203.

It is not a weakly prime, because it can be changed into another prime (21210201247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605100608 + 10605100609.

It is an arithmetic number, because the mean of its divisors is an integer number (10605100609).

Almost surely, 2^21210201217 is an apocalyptic number.

It is an amenable number.

21210201217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210201217 is an equidigital number, since it uses as much as digits as its factorization.

21210201217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 19.

Adding to 21210201217 its reverse (71210201212), we get a palindrome (92420402429).

The spelling of 21210201217 in words is "twenty-one billion, two hundred ten million, two hundred one thousand, two hundred seventeen".