21213312111 has 12 divisors (see below), whose sum is σ = 30674025720. Its totient is φ = 14127173520.

The previous prime is 21213312101. The next prime is 21213312119. The reversal of 21213312111 is 11121331212.

21213312111 is a `hidden beast` number, since 2 + 121 + 331 + 211 + 1 = 666.

It is not a de Polignac number, because 21213312111 - 2⁷ = 21213311983 is a prime.

It is a super-2 number, since 2×21213312111² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213312119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1243941 + ... + 1260878.

It is an arithmetic number, because the mean of its divisors is an integer number (2556168810).

Almost surely, 2^21213312111 is an apocalyptic number.

21213312111 is a deficient number, since it is larger than the sum of its proper divisors (9460713609).

21213312111 is a wasteful number, since it uses less digits than its factorization.

21213312111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2505766 (or 2505763 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

Adding to 21213312111 its reverse (11121331212), we get a palindrome (32334643323).

It can be divided in two parts, 2121331211 and 1, that added together give a palindrome (2121331212).

The spelling of 21213312111 in words is "twenty-one billion, two hundred thirteen million, three hundred twelve thousand, one hundred eleven".