1221021000217 has 2 divisors, whose sum is σ = 1221021000218. Its totient is φ = 1221021000216.

The previous prime is 1221021000203. The next prime is 1221021000229. The reversal of 1221021000217 is 7120001201221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1025107650576 + 195913349641 = 1012476^2 + 442621^2 .

It is an emirp because it is prime and its reverse (7120001201221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221021000217 - 2¹⁹ = 1221020475929 is a prime.

It is a super-2 number, since 2×1221021000217² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221021000194 and 1221021000203.

It is not a weakly prime, because it can be changed into another prime (1221021000247) 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, 610510500108 + 610510500109.

It is an arithmetic number, because the mean of its divisors is an integer number (610510500109).

Almost surely, 2^{1221021000217} is an apocalyptic number.

It is an amenable number.

1221021000217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221021000217 is an equidigital number, since it uses as much as digits as its factorization.

1221021000217 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 1221021000217 its reverse (7120001201221), we get a palindrome (8341022201438).

The spelling of 1221021000217 in words is "one trillion, two hundred twenty-one billion, twenty-one million, two hundred seventeen", and thus it is an aban number.