21384328 has 32 divisors (see below), whose sum is σ = 46460160. Its totient is φ = 9037440.

The previous prime is 21384313. The next prime is 21384347. The reversal of 21384328 is 82348312.

It is a self number, because there is not a number n which added to its sum of digits gives 21384328.

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, 1473 + ... + 6703.

It is an arithmetic number, because the mean of its divisors is an integer number (1451880).

Almost surely, 2^21384328 is an apocalyptic number.

21384328 is a gapful number since it is divisible by the number (28) 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 21384328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23230080).

21384328 is an abundant number, since it is smaller than the sum of its proper divisors (25075832).

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

21384328 is a wasteful number, since it uses less digits than its factorization.

21384328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5317 (or 5313 counting only the distinct ones).

The product of its digits is 9216, while the sum is 31.

The square root of 21384328 is about 4624.3191931354. The cubic root of 21384328 is about 277.5653196882.

It can be divided in two parts, 21384 and 328, that added together give a palindrome (21712).

The spelling of 21384328 in words is "twenty-one million, three hundred eighty-four thousand, three hundred twenty-eight".