21024304 has 40 divisors (see below), whose sum is σ = 48166560. Its totient is φ = 8698368.

The previous prime is 21024299. The next prime is 21024313. The reversal of 21024304 is 40342012.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12 + ... + 6484.

It is an arithmetic number, because the mean of its divisors is an integer number (1204164).

Almost surely, 2^21024304 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 21024304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24083280).

21024304 is an abundant number, since it is smaller than the sum of its proper divisors (27142256).

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

21024304 is a wasteful number, since it uses less digits than its factorization.

21024304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6517 (or 6511 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21024304 is about 4585.2267119522. The cubic root of 21024304 is about 275.9988097687.

Adding to 21024304 its reverse (40342012), we get a palindrome (61366316).

The spelling of 21024304 in words is "twenty-one million, twenty-four thousand, three hundred four".