221131111111 has 4 divisors (see below), whose sum is σ = 221828685912. Its totient is φ = 220433536312.

The previous prime is 221131111067. The next prime is 221131111121. The reversal of 221131111111 is 111111131122.

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 221131111111 - 2⁷ = 221131110983 is a prime.

It is a Duffinian number.

221131111111 is a modest number, since divided by 1111111 gives 22113 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221131111121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 348786925 + ... + 348787558.

It is an arithmetic number, because the mean of its divisors is an integer number (55457171478).

Almost surely, 2^221131111111 is an apocalyptic number.

221131111111 is a deficient number, since it is larger than the sum of its proper divisors (697574801).

221131111111 is an equidigital number, since it uses as much as digits as its factorization.

221131111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 697574800.

The product of its digits is 12, while the sum is 16.

Adding to 221131111111 its reverse (111111131122), we get a palindrome (332242242233).

The spelling of 221131111111 in words is "two hundred twenty-one billion, one hundred thirty-one million, one hundred eleven thousand, one hundred eleven".