21112011211 has 4 divisors (see below), whose sum is σ = 21114153424. Its totient is φ = 21109869000.

The previous prime is 21112011191. The next prime is 21112011287. The reversal of 21112011211 is 11211021112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21112011211 - 2⁷ = 21112011083 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112011191 and 21112011200.

It is not an unprimeable number, because it can be changed into a prime (21112012211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1056255 + ... + 1076056.

It is an arithmetic number, because the mean of its divisors is an integer number (5278538356).

Almost surely, 2^21112011211 is an apocalyptic number.

21112011211 is a deficient number, since it is larger than the sum of its proper divisors (2142213).

21112011211 is an equidigital number, since it uses as much as digits as its factorization.

21112011211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2142212.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21112011211 its reverse (11211021112), we get a palindrome (32323032323).

Subtracting from 21112011211 its reverse (11211021112), we obtain a palindrome (9900990099).

The spelling of 21112011211 in words is "twenty-one billion, one hundred twelve million, eleven thousand, two hundred eleven".