21220112 has 60 divisors (see below), whose sum is σ = 45361680. Its totient is φ = 9588096.

The previous prime is 21220109. The next prime is 21220153. The reversal of 21220112 is 21102212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21220093 and 21220102.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 255623 + ... + 255705.

It is an arithmetic number, because the mean of its divisors is an integer number (756028).

Almost surely, 2^21220112 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21220112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22680840).

21220112 is an abundant number, since it is smaller than the sum of its proper divisors (24141568).

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

21220112 is a wasteful number, since it uses less digits than its factorization.

21220112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21220112 is about 4606.5292791862. The cubic root of 21220112 is about 276.8529936293.

Adding to 21220112 its reverse (21102212), we get a palindrome (42322324).

The spelling of 21220112 in words is "twenty-one million, two hundred twenty thousand, one hundred twelve".