221211121111 has 4 divisors (see below), whose sum is σ = 226355565832. Its totient is φ = 216066676392.

The previous prime is 221211121099. The next prime is 221211121139. The reversal of 221211121111 is 111121112122.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221211121111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221211121141) 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, 2572222296 + ... + 2572222381.

It is an arithmetic number, because the mean of its divisors is an integer number (56588891458).

Almost surely, 2^221211121111 is an apocalyptic number.

221211121111 is a deficient number, since it is larger than the sum of its proper divisors (5144444721).

221211121111 is an equidigital number, since it uses as much as digits as its factorization.

221211121111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5144444720.

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

Adding to 221211121111 its reverse (111121112122), we get a palindrome (332332233233).

The spelling of 221211121111 in words is "two hundred twenty-one billion, two hundred eleven million, one hundred twenty-one thousand, one hundred eleven".