1221221221121 has 8 divisors (see below), whose sum is σ = 1339003980864. Its totient is φ = 1104565569520.

The previous prime is 1221221221111. The next prime is 1221221221151. The reversal of 1221221221121 is 1211221221221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221221221121 - 2¹⁸ = 1221220958977 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221221221093 and 1221221221102.

It is not an unprimeable number, because it can be changed into a prime (1221221221111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 281774765 + ... + 281779098.

It is an arithmetic number, because the mean of its divisors is an integer number (167375497608).

Almost surely, 2^{1221221221121} is an apocalyptic number.

1221221221121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221221221121 is a deficient number, since it is larger than the sum of its proper divisors (117782759743).

1221221221121 is a wasteful number, since it uses less digits than its factorization.

1221221221121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 563554071.

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

Adding to 1221221221121 its reverse (1211221221221), we get a palindrome (2432442442342).

It can be divided in two parts, 1221221221 and 121, that multiplied together give a palindrome (147767767741).

The spelling of 1221221221121 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-one thousand, one hundred twenty-one".