21212222211 has 24 divisors (see below), whose sum is σ = 31480928544. Its totient is φ = 13753618560.

The previous prime is 21212222201. The next prime is 21212222233. The reversal of 21212222211 is 11222221212.

It is a happy number.

21212222211 is a `hidden beast` number, since 21 + 212 + 222 + 211 = 666.

It is not a de Polignac number, because 21212222211 - 2¹¹ = 21212220163 is a prime.

It is a super-2 number, since 2×21212222211² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21212222201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 891015 + ... + 914511.

It is an arithmetic number, because the mean of its divisors is an integer number (1311705356).

Almost surely, 2^21212222211 is an apocalyptic number.

21212222211 is a deficient number, since it is larger than the sum of its proper divisors (10268706333).

21212222211 is a wasteful number, since it uses less digits than its factorization.

21212222211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26251 (or 26248 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

Adding to 21212222211 its reverse (11222221212), we get a palindrome (32434443423).

Subtracting from 21212222211 its reverse (11222221212), we obtain a palindrome (9990000999).

The spelling of 21212222211 in words is "twenty-one billion, two hundred twelve million, two hundred twenty-two thousand, two hundred eleven".