21102222222 has 80 divisors (see below), whose sum is σ = 48439881600. Its totient is φ = 6862596048.

The previous prime is 21102222191. The next prime is 21102222233. The reversal of 21102222222 is 22222220112.

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

21102222222 is a modest number, since divided by 222222 gives 21102 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 21102222195 and 21102222204.

It is a congruent number.

It is an unprimeable number.

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 39 ways as a sum of consecutive naturals, for example, 11834343 + ... + 11836125.

It is an arithmetic number, because the mean of its divisors is an integer number (605498520).

Almost surely, 2^21102222222 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21102222222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24219940800).

21102222222 is an abundant number, since it is smaller than the sum of its proper divisors (27337659378).

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

21102222222 is a wasteful number, since it uses less digits than its factorization.

21102222222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3539 (or 3530 counting only the distinct ones).

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

Adding to 21102222222 its reverse (22222220112), we get a palindrome (43324442334).

The spelling of 21102222222 in words is "twenty-one billion, one hundred two million, two hundred twenty-two thousand, two hundred twenty-two".