21331211111 has 48 divisors (see below), whose sum is σ = 25809848064. Its totient is φ = 17566730496.

The previous prime is 21331211071. The next prime is 21331211113. The reversal of 21331211111 is 11111213312.

It is not a de Polignac number, because 21331211111 - 2⁶ = 21331211047 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21331211111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331211113) 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, 49263551 + ... + 49263983.

It is an arithmetic number, because the mean of its divisors is an integer number (537705168).

Almost surely, 2^21331211111 is an apocalyptic number.

21331211111 is a deficient number, since it is larger than the sum of its proper divisors (4478636953).

21331211111 is a wasteful number, since it uses less digits than its factorization.

21331211111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820 (or 813 counting only the distinct ones).

The product of its digits is 36, while the sum is 17.

Adding to 21331211111 its reverse (11111213312), we get a palindrome (32442424423).

The spelling of 21331211111 in words is "twenty-one billion, three hundred thirty-one million, two hundred eleven thousand, one hundred eleven".