21120012211 has 4 divisors (see below), whose sum is σ = 21132020800. Its totient is φ = 21108003624.

The previous prime is 21120012197. The next prime is 21120012253. The reversal of 21120012211 is 11221002112.

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 21120012211 - 2¹³ = 21120004019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21120012191 and 21120012200.

It is not an unprimeable number, because it can be changed into a prime (21120012811) 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, 6001656 + ... + 6005173.

It is an arithmetic number, because the mean of its divisors is an integer number (5283005200).

Almost surely, 2^21120012211 is an apocalyptic number.

21120012211 is a deficient number, since it is larger than the sum of its proper divisors (12008589).

21120012211 is a wasteful number, since it uses less digits than its factorization.

21120012211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12008588.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21120012211 its reverse (11221002112), we get a palindrome (32341014323).

The spelling of 21120012211 in words is "twenty-one billion, one hundred twenty million, twelve thousand, two hundred eleven".