21121112211 has 16 divisors (see below), whose sum is σ = 28275350400. Its totient is φ = 14023923200.

The previous prime is 21121112209. The next prime is 21121112237. The reversal of 21121112211 is 11221112112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21121112211 - 2¹ = 21121112209 is a prime.

It is a super-2 number, since 2×21121112211² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121112011) 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, 744436 + ... + 772286.

It is an arithmetic number, because the mean of its divisors is an integer number (1767209400).

Almost surely, 2^21121112211 is an apocalyptic number.

21121112211 is a deficient number, since it is larger than the sum of its proper divisors (7154238189).

21121112211 is a wasteful number, since it uses less digits than its factorization.

21121112211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28866.

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

Adding to 21121112211 its reverse (11221112112), we get a palindrome (32342224323).

Subtracting from 21121112211 its reverse (11221112112), we obtain a palindrome (9900000099).

The spelling of 21121112211 in words is "twenty-one billion, one hundred twenty-one million, one hundred twelve thousand, two hundred eleven".