21220121211 has 16 divisors (see below), whose sum is σ = 28404729600. Its totient is φ = 14091196320.

The previous prime is 21220121203. The next prime is 21220121297. The reversal of 21220121211 is 11212102212.

It is not a de Polignac number, because 21220121211 - 2³ = 21220121203 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21220126211) 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 15 ways as a sum of consecutive naturals, for example, 1437876 + ... + 1452558.

It is an arithmetic number, because the mean of its divisors is an integer number (1775295600).

Almost surely, 2^21220121211 is an apocalyptic number.

21220121211 is a deficient number, since it is larger than the sum of its proper divisors (7184608389).

21220121211 is a wasteful number, since it uses less digits than its factorization.

21220121211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16546.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21220121211 its reverse (11212102212), we get a palindrome (32432223423).

The spelling of 21220121211 in words is "twenty-one billion, two hundred twenty million, one hundred twenty-one thousand, two hundred eleven".