21131331111 has 20 divisors (see below), whose sum is σ = 34436244744. Its totient is φ = 12806866800.

The previous prime is 21131331077. The next prime is 21131331113. The reversal of 21131331111 is 11113313112.

21131331111 is a `hidden beast` number, since 211 + 313 + 31 + 111 = 666.

It is not a de Polignac number, because 21131331111 - 2²⁷ = 20997113383 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131331113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 11857320 + ... + 11859101.

Almost surely, 2^21131331111 is an apocalyptic number.

21131331111 is a deficient number, since it is larger than the sum of its proper divisors (13304913633).

21131331111 is a wasteful number, since it uses less digits than its factorization.

21131331111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23716444 (or 23716435 counting only the distinct ones).

The product of its digits is 54, while the sum is 18.

Adding to 21131331111 its reverse (11113313112), we get a palindrome (32244644223).

The spelling of 21131331111 in words is "twenty-one billion, one hundred thirty-one million, three hundred thirty-one thousand, one hundred eleven".