Adding to 421824 its reverse (428124), we get a palindrome (849948).
421824 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.
It is an ABA number since it can be written as A⋅BA, here for A=3, B=52.
It is a nude number because it is divisible by every one of its digits.
It is a self number, because there is not a number n which added to its sum of digits gives 421824.
It is a congruent number.
It is an unprimeable number.
421824 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
2421824 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 421824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (604520).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
421824 is an equidigital number, since it uses as much as digits as its factorization.
421824 is an evil number, because the sum of its binary digits is even.
The square root of 421824 is about 649.4797918334. The cubic root of 421824 is about 74.9969776560.
The spelling of 421824 in words is "four hundred twenty-one thousand, eight hundred twenty-four".