21211122222 has 48 divisors (see below), whose sum is σ = 46564539840. Its totient is φ = 6977071296.

The previous prime is 21211122199. The next prime is 21211122227. The reversal of 21211122222 is 22222111212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21211122195 and 21211122204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211122227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3974668 + ... + 3980000.

It is an arithmetic number, because the mean of its divisors is an integer number (970094580).

Almost surely, 2^21211122222 is an apocalyptic number.

21211122222 is an abundant number, since it is smaller than the sum of its proper divisors (25353417618).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21211122222 is a wasteful number, since it uses less digits than its factorization.

21211122222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8217 (or 8214 counting only the distinct ones).

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

Adding to 21211122222 its reverse (22222111212), we get a palindrome (43433233434).

The spelling of 21211122222 in words is "twenty-one billion, two hundred eleven million, one hundred twenty-two thousand, two hundred twenty-two".