1221111211111 has 48 divisors (see below), whose sum is σ = 1396688940864. Its totient is φ = 1066028480000.

The previous prime is 1221111211057. The next prime is 1221111211141. The reversal of 1221111211111 is 1111121111221.

It is not a de Polignac number, because 1221111211111 - 2⁷ = 1221111210983 is a prime.

It is a super-2 number, since 2×1221111211111² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221111211141) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 86676510 + ... + 86690596.

It is an arithmetic number, because the mean of its divisors is an integer number (29097686268).

Almost surely, 2^{1221111211111} is an apocalyptic number.

1221111211111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221111211111 is a deficient number, since it is larger than the sum of its proper divisors (175577729753).

1221111211111 is a wasteful number, since it uses less digits than its factorization.

1221111211111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14424 (or 14413 counting only the distinct ones).

The product of its digits is 8, while the sum is 16.

Adding to 1221111211111 its reverse (1111121111221), we get a palindrome (2332232322332).

The spelling of 1221111211111 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, two hundred eleven thousand, one hundred eleven".