1221122211221 has 16 divisors (see below), whose sum is σ = 1371720261888. Its totient is φ = 1086491660320.

The previous prime is 1221122211109. The next prime is 1221122211233.

1221122211221 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1221122211221 - 2²⁶ = 1221055102357 is a prime.

It is a super-2 number, since 2×1221122211221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221122211193 and 1221122211202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221122211241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9697520 + ... + 9822633.

It is an arithmetic number, because the mean of its divisors is an integer number (85732516368).

Almost surely, 2^{1221122211221} is an apocalyptic number.

1221122211221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221122211221 is a deficient number, since it is larger than the sum of its proper divisors (150598050667).

1221122211221 is an equidigital number, since it uses as much as digits as its factorization.

1221122211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19520233 (or 19520211 counting only the distinct ones).

The product of its digits is 128, while the sum is 20.

The spelling of 1221122211221 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-two million, two hundred eleven thousand, two hundred twenty-one".