21424304 has 40 divisors (see below), whose sum is σ = 46403280. Its totient is φ = 9497600.

The previous prime is 21424303. The next prime is 21424313. The reversal of 21424304 is 40342412.

It is not an unprimeable number, because it can be changed into a prime (21424303) 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 7 ways as a sum of consecutive naturals, for example, 5732 + ... + 8700.

It is an arithmetic number, because the mean of its divisors is an integer number (1160082).

Almost surely, 2^21424304 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 21424304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23201640).

21424304 is an abundant number, since it is smaller than the sum of its proper divisors (24978976).

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

21424304 is a wasteful number, since it uses less digits than its factorization.

21424304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3029 (or 3023 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 21424304 is about 4628.6395409450. The cubic root of 21424304 is about 277.7381728187.

Adding to 21424304 its reverse (40342412), we get a palindrome (61766716).

It can be divided in two parts, 2142 and 4304, that added together give a palindrome (6446).

The spelling of 21424304 in words is "twenty-one million, four hundred twenty-four thousand, three hundred four".