21456384 has 80 divisors (see below), whose sum is σ = 58351920. Its totient is φ = 7004160.

The previous prime is 21456373. The next prime is 21456403. The reversal of 21456384 is 48365412.

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, 93582 + ... + 93810.

It is an arithmetic number, because the mean of its divisors is an integer number (729399).

Almost surely, 2^21456384 is an apocalyptic number.

21456384 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21456384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29175960).

21456384 is an abundant number, since it is smaller than the sum of its proper divisors (36895536).

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

21456384 is an equidigital number, since it uses as much as digits as its factorization.

21456384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311 (or 295 counting only the distinct ones).

The product of its digits is 23040, while the sum is 33.

The square root of 21456384 is about 4632.1036257839. The cubic root of 21456384 is about 277.8767288123.

The spelling of 21456384 in words is "twenty-one million, four hundred fifty-six thousand, three hundred eighty-four".