21212231111 has 8 divisors (see below), whose sum is σ = 21323787648. Its totient is φ = 21100779000.

The previous prime is 21212231039. The next prime is 21212231113. The reversal of 21212231111 is 11113221212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21212231111 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21212231111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212231113) 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 7 ways as a sum of consecutive naturals, for example, 399326 + ... + 449316.

It is an arithmetic number, because the mean of its divisors is an integer number (2665473456).

Almost surely, 2^21212231111 is an apocalyptic number.

21212231111 is a deficient number, since it is larger than the sum of its proper divisors (111556537).

21212231111 is a wasteful number, since it uses less digits than its factorization.

21212231111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52213.

The product of its digits is 48, while the sum is 17.

Adding to 21212231111 its reverse (11113221212), we get a palindrome (32325452323).

The spelling of 21212231111 in words is "twenty-one billion, two hundred twelve million, two hundred thirty-one thousand, one hundred eleven".