1221121111211 has 16 divisors (see below), whose sum is σ = 1315879741440. Its totient is φ = 1129435786080.

The previous prime is 1221121111193. The next prime is 1221121111213. The reversal of 1221121111211 is 1121111211221.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221121111211 is a prime.

It is a super-2 number, since 2×1221121111211² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221121111211.

It is not an unprimeable number, because it can be changed into a prime (1221121111213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1470326 + ... + 2145716.

It is an arithmetic number, because the mean of its divisors is an integer number (82242483840).

Almost surely, 2^{1221121111211} is an apocalyptic number.

1221121111211 is a deficient number, since it is larger than the sum of its proper divisors (94758630229).

1221121111211 is a wasteful number, since it uses less digits than its factorization.

1221121111211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 677666.

The product of its digits is 16, while the sum is 17.

Adding to 1221121111211 its reverse (1121111211221), we get a palindrome (2342232322432).

The spelling of 1221121111211 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, two hundred eleven".