1221122221121 has 32 divisors (see below), whose sum is σ = 1389248381952. Its totient is φ = 1063260000000.

The previous prime is 1221122221117. The next prime is 1221122221157. The reversal of 1221122221121 is 1211222211221.

It is not a de Polignac number, because 1221122221121 - 2² = 1221122221117 is a prime.

It is a super-2 number, since 2×1221122221121² (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 = 1221122221093 and 1221122221102.

It is not an unprimeable number, because it can be changed into a prime (1221722221121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 123328271 + ... + 123338171.

It is an arithmetic number, because the mean of its divisors is an integer number (43414011936).

Almost surely, 2^{1221122221121} is an apocalyptic number.

1221122221121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221122221121 is a deficient number, since it is larger than the sum of its proper divisors (168126160831).

1221122221121 is a wasteful number, since it uses less digits than its factorization.

1221122221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13625.

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

Adding to 1221122221121 its reverse (1211222211221), we get a palindrome (2432344432342).

It can be divided in two parts, 1 and 221122221121, that added together give a palindrome (221122221122).

The spelling of 1221122221121 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-two million, two hundred twenty-one thousand, one hundred twenty-one".