21121311211 has 48 divisors (see below), whose sum is σ = 28712099584. Its totient is φ = 15118488000.

The previous prime is 21121311191. The next prime is 21121311307. The reversal of 21121311211 is 11211312112.

It is a happy number.

It is not a de Polignac number, because 21121311211 - 2¹¹ = 21121309163 is a prime.

It is a super-2 number, since 2×21121311211² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121311011) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2318776 + ... + 2327866.

Almost surely, 2^21121311211 is an apocalyptic number.

21121311211 is a deficient number, since it is larger than the sum of its proper divisors (7590788373).

21121311211 is a wasteful number, since it uses less digits than its factorization.

21121311211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9344 (or 9333 counting only the distinct ones).

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

Adding to 21121311211 its reverse (11211312112), we get a palindrome (32332623323).

Subtracting from 21121311211 its reverse (11211312112), we obtain a palindrome (9909999099).

The spelling of 21121311211 in words is "twenty-one billion, one hundred twenty-one million, three hundred eleven thousand, two hundred eleven".