21212012202217 has 2 divisors, whose sum is σ = 21212012202218. Its totient is φ = 21212012202216.

The previous prime is 21212012202211. The next prime is 21212012202221. The reversal of 21212012202217 is 71220221021212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20947729843161 + 264282359056 = 4576869^2 + 514084^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212012202217 - 2⁷ = 21212012202089 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21212012202191 and 21212012202200.

It is not a weakly prime, because it can be changed into another prime (21212012202211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606006101108 + 10606006101109.

It is an arithmetic number, because the mean of its divisors is an integer number (10606006101109).

Almost surely, 2^{21212012202217} is an apocalyptic number.

It is an amenable number.

21212012202217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212012202217 is an equidigital number, since it uses as much as digits as its factorization.

21212012202217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 896, while the sum is 25.

Adding to 21212012202217 its reverse (71220221021212), we get a palindrome (92432233223429).

The spelling of 21212012202217 in words is "twenty-one trillion, two hundred twelve billion, twelve million, two hundred two thousand, two hundred seventeen".