21845824 has 168 divisors, whose sum is σ = 60537344. Its totient is φ = 7603200.

The previous prime is 21845809. The next prime is 21845827. The reversal of 21845824 is 42854812.

Its product of digits (20480) is a multiple of the sum of its prime divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 21845824.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21845827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 704689 + ... + 704719.

Almost surely, 2^21845824 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 21845824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30268672).

21845824 is an abundant number, since it is smaller than the sum of its proper divisors (38691520).

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

21845824 is a wasteful number, since it uses less digits than its factorization.

21845824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85 (or 64 counting only the distinct ones).

The product of its digits is 20480, while the sum is 34.

The square root of 21845824 is about 4673.9516471611. The cubic root of 21845824 is about 279.5478416531.

It can be divided in two parts, 2184 and 5824, that added together give a palindrome (8008).

The spelling of 21845824 in words is "twenty-one million, eight hundred forty-five thousand, eight hundred twenty-four".