Adding to 421421824 its reverse (428124124), we get a palindrome (849545948).
It is a nude number because it is divisible by every one of its digits.
It is an unprimeable number.
Almost surely, 2421421824 is an apocalyptic number.
421421824 is the 16762-nd centered triangular number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 421421824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (462107520).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
421421824 is a wasteful number, since it uses less digits than its factorization.
421421824 is an odious number, because the sum of its binary digits is odd.
The square root of 421421824 is about 20528.5611770528. The cubic root of 421421824 is about 749.7313550439.
The spelling of 421421824 in words is "four hundred twenty-one million, four hundred twenty-one thousand, eight hundred twenty-four".