21220001205217 has 2 divisors, whose sum is σ = 21220001205218. Its totient is φ = 21220001205216.

The previous prime is 21220001205197. The next prime is 21220001205223. The reversal of 21220001205217 is 71250210002212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17161996431616 + 4058004773601 = 4142704^2 + 2014449^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220001205217 - 2³¹ = 21217853721569 is a prime.

It is a super-2 number, since 2×21220001205217² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21220001205191 and 21220001205200.

It is not a weakly prime, because it can be changed into another prime (21220001202217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610000602608 + 10610000602609.

It is an arithmetic number, because the mean of its divisors is an integer number (10610000602609).

Almost surely, 2^{21220001205217} is an apocalyptic number.

It is an amenable number.

21220001205217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220001205217 is an equidigital number, since it uses as much as digits as its factorization.

21220001205217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 25.

Adding to 21220001205217 its reverse (71250210002212), we get a palindrome (92470211207429).

The spelling of 21220001205217 in words is "twenty-one trillion, two hundred twenty billion, one million, two hundred five thousand, two hundred seventeen".