21211121211 has 16 divisors (see below), whose sum is σ = 32869536000. Its totient is φ = 11915205408.

The previous prime is 21211121207. The next prime is 21211121279. The reversal of 21211121211 is 11212111212.

It is a happy number.

It is not a de Polignac number, because 21211121211 - 2² = 21211121207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21211121611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8558536 + ... + 8561013.

It is an arithmetic number, because the mean of its divisors is an integer number (2054346000).

Almost surely, 2^21211121211 is an apocalyptic number.

21211121211 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21211121211 is a deficient number, since it is larger than the sum of its proper divisors (11658414789).

21211121211 is a wasteful number, since it uses less digits than its factorization.

21211121211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17119618.

The product of its digits is 16, while the sum is 15.

Adding to 21211121211 its reverse (11212111212), we get a palindrome (32423232423).

Subtracting from 21211121211 its reverse (11212111212), we obtain a palindrome (9999009999).

It can be divided in two parts, 212111212 and 11, that multiplied together give a palindrome (2333223332).

The spelling of 21211121211 in words is "twenty-one billion, two hundred eleven million, one hundred twenty-one thousand, two hundred eleven".