21211020211 has 4 divisors (see below), whose sum is σ = 21236856624. Its totient is φ = 21185183800.

The previous prime is 21211020191. The next prime is 21211020269. The reversal of 21211020211 is 11202011212.

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 21211020211 - 2³¹ = 19063536563 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211020191 and 21211020200.

It is not an unprimeable number, because it can be changed into a prime (21211029211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12916975 + ... + 12918616.

It is an arithmetic number, because the mean of its divisors is an integer number (5309214156).

Almost surely, 2^21211020211 is an apocalyptic number.

21211020211 is a deficient number, since it is larger than the sum of its proper divisors (25836413).

21211020211 is an equidigital number, since it uses as much as digits as its factorization.

21211020211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25836412.

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

Adding to 21211020211 its reverse (11202011212), we get a palindrome (32413031423).

The spelling of 21211020211 in words is "twenty-one billion, two hundred eleven million, twenty thousand, two hundred eleven".