21063328 has 48 divisors (see below), whose sum is σ = 48728736. Its totient is φ = 8835840.

The previous prime is 21063311. The next prime is 21063373. The reversal of 21063328 is 82336012.

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, 2275 + ... + 6877.

It is an arithmetic number, because the mean of its divisors is an integer number (1015182).

Almost surely, 2^21063328 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 21063328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24364368).

21063328 is an abundant number, since it is smaller than the sum of its proper divisors (27665408).

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

21063328 is a wasteful number, since it uses less digits than its factorization.

21063328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4637 (or 4629 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 21063328 is about 4589.4801448530. The cubic root of 21063328 is about 276.1694681414.

The spelling of 21063328 in words is "twenty-one million, sixty-three thousand, three hundred twenty-eight".