21024224 has 24 divisors (see below), whose sum is σ = 44576280. Its totient is φ = 9703296.

The previous prime is 21024221. The next prime is 21024253. The reversal of 21024224 is 42242012.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24854 + ... + 25685.

It is an arithmetic number, because the mean of its divisors is an integer number (1857345).

Almost surely, 2^21024224 is an apocalyptic number.

It is an amenable number.

21024224 is an abundant number, since it is smaller than the sum of its proper divisors (23552056).

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

21024224 is a wasteful number, since it uses less digits than its factorization.

21024224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50562 (or 50554 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 21024224 is about 4585.2179882749. The cubic root of 21024224 is about 275.9984596987.

Adding to 21024224 its reverse (42242012), we get a palindrome (63266236).

The spelling of 21024224 in words is "twenty-one million, twenty-four thousand, two hundred twenty-four".