1221021001217 has 2 divisors, whose sum is σ = 1221021001218. Its totient is φ = 1221021001216.

The previous prime is 1221021001183. The next prime is 1221021001231. The reversal of 1221021001217 is 7121001201221.

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., 631835804161 + 589185197056 = 794881^2 + 767584^2 .

It is an emirp because it is prime and its reverse (7121001201221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221021001217 - 2¹² = 1221020997121 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221021000217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610510500608 + 610510500609.

It is an arithmetic number, because the mean of its divisors is an integer number (610510500609).

Almost surely, 2^{1221021001217} is an apocalyptic number.

It is an amenable number.

1221021001217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221021001217 is an equidigital number, since it uses as much as digits as its factorization.

1221021001217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112, while the sum is 20.

Adding to 1221021001217 its reverse (7121001201221), we get a palindrome (8342022202438).

The spelling of 1221021001217 in words is "one trillion, two hundred twenty-one billion, twenty-one million, one thousand, two hundred seventeen".