1221220013121 has 12 divisors (see below), whose sum is σ = 1764029114640. Its totient is φ = 814126067160.

The previous prime is 1221220013099. The next prime is 1221220013147. The reversal of 1221220013121 is 1213100221221.

It is not a de Polignac number, because 1221220013121 - 2¹⁷ = 1221219882049 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221220013094 and 1221220013103.

It is not an unprimeable number, because it can be changed into a prime (1221220013021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1337631 + ... + 2057108.

It is an arithmetic number, because the mean of its divisors is an integer number (147002426220).

Almost surely, 2^{1221220013121} is an apocalyptic number.

It is an amenable number.

1221220013121 is a deficient number, since it is larger than the sum of its proper divisors (542809101519).

1221220013121 is a wasteful number, since it uses less digits than its factorization.

1221220013121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3434716 (or 3434713 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 1221220013121 its reverse (1213100221221), we get a palindrome (2434320234342).

The spelling of 1221220013121 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, thirteen thousand, one hundred twenty-one".