1220221021121 has 4 divisors (see below), whose sum is σ = 1221321311700. Its totient is φ = 1219120730544.

The previous prime is 1220221021109. The next prime is 1220221021153. The reversal of 1220221021121 is 1211201220221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 455490010000 + 764731011121 = 674900^2 + 874489^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220221021121 - 2¹⁰ = 1220221020097 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1220221021121.

It is not an unprimeable number, because it can be changed into a prime (1220221021181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 550143626 + ... + 550145843.

It is an arithmetic number, because the mean of its divisors is an integer number (305330327925).

Almost surely, 2^{1220221021121} is an apocalyptic number.

It is an amenable number.

1220221021121 is a deficient number, since it is larger than the sum of its proper divisors (1100290579).

1220221021121 is a wasteful number, since it uses less digits than its factorization.

1220221021121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1100290578.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1220221021121 its reverse (1211201220221), we get a palindrome (2431422241342).

The spelling of 1220221021121 in words is "one trillion, two hundred twenty billion, two hundred twenty-one million, twenty-one thousand, one hundred twenty-one".