21024216 has 48 divisors (see below), whose sum is σ = 57493800. Its totient is φ = 6940032.

The previous prime is 21024209. The next prime is 21024221. The reversal of 21024216 is 61242012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 6340 + ... + 9068.

Almost surely, 2^21024216 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 21024216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28746900).

21024216 is an abundant number, since it is smaller than the sum of its proper divisors (36469584).

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

21024216 is a wasteful number, since it uses less digits than its factorization.

21024216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2848 (or 2841 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21024216 is about 4585.2171159063. The cubic root of 21024216 is about 275.9984246917.

Adding to 21024216 its reverse (61242012), we get a palindrome (82266228).

The spelling of 21024216 in words is "twenty-one million, twenty-four thousand, two hundred sixteen".