21201222222 has 48 divisors (see below), whose sum is σ = 47260114512. Its totient is φ = 6864030720.

The previous prime is 21201222209. The next prime is 21201222253. The reversal of 21201222222 is 22222210212.

21201222222 is a `hidden beast` number, since 21 + 201 + 222 + 222 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21201222195 and 21201222204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 356697 + ... + 411867.

It is an arithmetic number, because the mean of its divisors is an integer number (984585719).

Almost surely, 2^21201222222 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21201222222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23630057256).

21201222222 is an abundant number, since it is smaller than the sum of its proper divisors (26058892290).

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

21201222222 is a wasteful number, since it uses less digits than its factorization.

21201222222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55793 (or 55790 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21201222222 its reverse (22222210212), we get a palindrome (43423432434).

The spelling of 21201222222 in words is "twenty-one billion, two hundred one million, two hundred twenty-two thousand, two hundred twenty-two".