1221220221221 has 24 divisors (see below), whose sum is σ = 1652102132352. Its totient is φ = 878400151200.

The previous prime is 1221220221157. The next prime is 1221220221239.

1221220221221 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1221220221221 - 2⁶ = 1221220221157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221220221193 and 1221220221202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221220221241) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 55443545 + ... + 55465566.

It is an arithmetic number, because the mean of its divisors is an integer number (68837588848).

Almost surely, 2^{1221220221221} is an apocalyptic number.

1221220221221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221220221221 is a deficient number, since it is larger than the sum of its proper divisors (430881911131).

1221220221221 is a wasteful number, since it uses less digits than its factorization.

1221220221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110909153 (or 110909142 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

It can be divided in two parts, 1221220 and 221221, that added together give a palindrome (1442441).

The spelling of 1221220221221 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, two hundred twenty-one thousand, two hundred twenty-one".