21112311220 has 576 divisors, whose sum is σ = 65505646080. Its totient is φ = 5514854400.

The previous prime is 21112311173. The next prime is 21112311223. The reversal of 21112311220 is 2211321112.

It is a junction number, because it is equal to n+sod(n) for n = 21112311194 and 21112311203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112311223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 237216936 + ... + 237217024.

It is an arithmetic number, because the mean of its divisors is an integer number (113725080).

Almost surely, 2^21112311220 is an apocalyptic number.

21112311220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21112311220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32752823040).

21112311220 is an abundant number, since it is smaller than the sum of its proper divisors (44393334860).

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

21112311220 is a wasteful number, since it uses less digits than its factorization.

21112311220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204 (or 185 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21112311220 its reverse (2211321112), we get a palindrome (23323632332).

The spelling of 21112311220 in words is "twenty-one billion, one hundred twelve million, three hundred eleven thousand, two hundred twenty".