1221111010111 has 4 divisors (see below), whose sum is σ = 1221190894000. Its totient is φ = 1221031126224.

The previous prime is 1221111010099. The next prime is 1221111010199. The reversal of 1221111010111 is 1110101111221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221111010111 - 2²⁷ = 1220976792383 is a prime.

It is a super-2 number, since 2×1221111010111² (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 = 1221111010091 and 1221111010100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221111010411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39919011 + ... + 39949588.

It is an arithmetic number, because the mean of its divisors is an integer number (305297723500).

Almost surely, 2^{1221111010111} is an apocalyptic number.

1221111010111 is a deficient number, since it is larger than the sum of its proper divisors (79883889).

1221111010111 is an equidigital number, since it uses as much as digits as its factorization.

1221111010111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79883888.

The product of its (nonzero) digits is 4, while the sum is 13.

Adding to 1221111010111 its reverse (1110101111221), we get a palindrome (2331212121332).

It can be divided in two parts, 1221 and 111010111, that multiplied together give a palindrome (135543345531).

The spelling of 1221111010111 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, ten thousand, one hundred eleven".