1221001221211 has 12 divisors (see below), whose sum is σ = 1289618321952. Its totient is φ = 1155865851504.

The previous prime is 1221001221203. The next prime is 1221001221217. The reversal of 1221001221211 is 1121221001221.

It is not a de Polignac number, because 1221001221211 - 2³ = 1221001221203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221001221217) 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 in 11 ways as a sum of consecutive naturals, for example, 795360 + ... + 1753453.

It is an arithmetic number, because the mean of its divisors is an integer number (107468193496).

Almost surely, 2^{1221001221211} is an apocalyptic number.

1221001221211 is a deficient number, since it is larger than the sum of its proper divisors (68617100741).

1221001221211 is a wasteful number, since it uses less digits than its factorization.

1221001221211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2550178 (or 2550159 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221001221211 its reverse (1121221001221), we get a palindrome (2342222222432).

The spelling of 1221001221211 in words is "one trillion, two hundred twenty-one billion, one million, two hundred twenty-one thousand, two hundred eleven".