21321031111 has 4 divisors (see below), whose sum is σ = 21520293192. Its totient is φ = 21121769032.

The previous prime is 21321031063. The next prime is 21321031139. The reversal of 21321031111 is 11113012312.

It is a happy number.

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 21321031111 - 2¹¹ = 21321029063 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 (21321031141) 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, 99630880 + ... + 99631093.

It is an arithmetic number, because the mean of its divisors is an integer number (5380073298).

Almost surely, 2^21321031111 is an apocalyptic number.

21321031111 is a deficient number, since it is larger than the sum of its proper divisors (199262081).

21321031111 is a wasteful number, since it uses less digits than its factorization.

21321031111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199262080.

The product of its (nonzero) digits is 36, while the sum is 16.

Adding to 21321031111 its reverse (11113012312), we get a palindrome (32434043423).

The spelling of 21321031111 in words is "twenty-one billion, three hundred twenty-one million, thirty-one thousand, one hundred eleven".