21804112 has 20 divisors (see below), whose sum is σ = 46086336. Its totient is φ = 9910880.

The previous prime is 21804109. The next prime is 21804113. The reversal of 21804112 is 21140812.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21804112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21804113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61768 + ... + 62119.

Almost surely, 2^21804112 is an apocalyptic number.

21804112 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21804112 is an abundant number, since it is smaller than the sum of its proper divisors (24282224).

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

21804112 is a wasteful number, since it uses less digits than its factorization.

21804112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123906 (or 123900 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 21804112 is about 4669.4873380276. The cubic root of 21804112 is about 279.3698071861.

Adding to 21804112 its reverse (21140812), we get a palindrome (42944924).

The spelling of 21804112 in words is "twenty-one million, eight hundred four thousand, one hundred twelve".