21113121211 has 16 divisors (see below), whose sum is σ = 25988838400. Its totient is φ = 16702663968.

The previous prime is 21113121191. The next prime is 21113121229. The reversal of 21113121211 is 11212131112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21113121211 - 2⁵ = 21113121179 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21111121211) 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 15 ways as a sum of consecutive naturals, for example, 1166650 + ... + 1184608.

It is an arithmetic number, because the mean of its divisors is an integer number (1624302400).

Almost surely, 2^21113121211 is an apocalyptic number.

21113121211 is a deficient number, since it is larger than the sum of its proper divisors (4875717189).

21113121211 is a wasteful number, since it uses less digits than its factorization.

21113121211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30898.

The product of its digits is 24, while the sum is 16.

Adding to 21113121211 its reverse (11212131112), we get a palindrome (32325252323).

Subtracting from 21113121211 its reverse (11212131112), we obtain a palindrome (9900990099).

The spelling of 21113121211 in words is "twenty-one billion, one hundred thirteen million, one hundred twenty-one thousand, two hundred eleven".