21242112 has 72 divisors (see below), whose sum is σ = 59897376. Its totient is φ = 6660096.

The previous prime is 21242101. The next prime is 21242131. The reversal of 21242112 is 21124212.

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21242091 and 21242100.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12243 + ... + 13869.

It is an arithmetic number, because the mean of its divisors is an integer number (831908).

Almost surely, 2^21242112 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 21242112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29948688).

21242112 is an abundant number, since it is smaller than the sum of its proper divisors (38655264).

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

21242112 is a wasteful number, since it uses less digits than its factorization.

21242112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1663 (or 1649 counting only the distinct ones).

The product of its digits is 64, while the sum is 15.

The square root of 21242112 is about 4608.9165755088. The cubic root of 21242112 is about 276.9486365772.

Adding to 21242112 its reverse (21124212), we get a palindrome (42366324).

It can be divided in two parts, 212 and 42112, that added together give a palindrome (42324).

The spelling of 21242112 in words is "twenty-one million, two hundred forty-two thousand, one hundred twelve".