21212210211211 has 4 divisors (see below), whose sum is σ = 21294747994392. Its totient is φ = 21129672428032.

The previous prime is 21212210211149. The next prime is 21212210211221. The reversal of 21212210211211 is 11211201221212.

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 21212210211211 - 2¹¹ = 21212210209163 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212210211221) 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, 41268891205 + ... + 41268891718.

It is an arithmetic number, because the mean of its divisors is an integer number (5323686998598).

Almost surely, 2^{21212210211211} is an apocalyptic number.

21212210211211 is a deficient number, since it is larger than the sum of its proper divisors (82537783181).

21212210211211 is an equidigital number, since it uses as much as digits as its factorization.

21212210211211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82537783180.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21212210211211 its reverse (11211201221212), we get a palindrome (32423411432423).

The spelling of 21212210211211 in words is "twenty-one trillion, two hundred twelve billion, two hundred ten million, two hundred eleven thousand, two hundred eleven".