1211220221121 has 6 divisors (see below), whose sum is σ = 1749540319410. Its totient is φ = 807480147408.

The previous prime is 1211220221093. The next prime is 1211220221137.

1211220221121 is a `hidden beast` number, since 1 + 211 + 220 + 2 + 211 + 21 = 666.

1211220221121 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 1083599803521 + 127620417600 = 1040961^2 + 357240^2 .

It is not a de Polignac number, because 1211220221121 - 2¹⁴ = 1211220204737 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1211220221094 and 1211220221103.

It is not an unprimeable number, because it can be changed into a prime (1211220221021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67290012276 + ... + 67290012293.

It is an arithmetic number, because the mean of its divisors is an integer number (291590053235).

Almost surely, 2^{1211220221121} is an apocalyptic number.

It is an amenable number.

1211220221121 is a deficient number, since it is larger than the sum of its proper divisors (538320098289).

1211220221121 is a wasteful number, since it uses less digits than its factorization.

1211220221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134580024575 (or 134580024572 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

It can be divided in two parts, 1211220 and 221121, that added together give a palindrome (1432341).

The spelling of 1211220221121 in words is "one trillion, two hundred eleven billion, two hundred twenty million, two hundred twenty-one thousand, one hundred twenty-one".