21222111220 has 12 divisors (see below), whose sum is σ = 44566433604. Its totient is φ = 8488844480.

The previous prime is 21222111203. The next prime is 21222111227. The reversal of 21222111220 is 2211122212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 10364054416 + 10858056804 = 101804^2 + 104202^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21222111194 and 21222111203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222111227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 530552761 + ... + 530552800.

It is an arithmetic number, because the mean of its divisors is an integer number (3713869467).

Almost surely, 2^21222111220 is an apocalyptic number.

21222111220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222111220 is an abundant number, since it is smaller than the sum of its proper divisors (23344322384).

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

21222111220 is a wasteful number, since it uses less digits than its factorization.

21222111220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1061105570 (or 1061105568 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21222111220 its reverse (2211122212), we get a palindrome (23433233432).

The spelling of 21222111220 in words is "twenty-one billion, two hundred twenty-two million, one hundred eleven thousand, two hundred twenty".