1217355240221 has 2 divisors, whose sum is σ = 1217355240222. Its totient is φ = 1217355240220.

The previous prime is 1217355240193. The next prime is 1217355240301. The reversal of 1217355240221 is 1220425537121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 624077880196 + 593277360025 = 789986^2 + 770245^2 .

It is a cyclic number.

It is not a de Polignac number, because 1217355240221 - 2¹⁰ = 1217355239197 is a prime.

It is a super-2 number, since 2×1217355240221² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1217355245221) 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, 608677620110 + 608677620111.

It is an arithmetic number, because the mean of its divisors is an integer number (608677620111).

Almost surely, 2^{1217355240221} is an apocalyptic number.

It is an amenable number.

1217355240221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1217355240221 is an equidigital number, since it uses as much as digits as its factorization.

1217355240221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 33600, while the sum is 35.

The spelling of 1217355240221 in words is "one trillion, two hundred seventeen billion, three hundred fifty-five million, two hundred forty thousand, two hundred twenty-one".