21335328 has 144 divisors (see below), whose sum is σ = 73120320. Its totient is φ = 5764608.

The previous prime is 21335311. The next prime is 21335339. The reversal of 21335328 is 82353312.

21335328 is a `hidden beast` number, since 2 + 1 + 335 + 328 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38026 + ... + 38582.

It is an arithmetic number, because the mean of its divisors is an integer number (507780).

Almost surely, 2^21335328 is an apocalyptic number.

21335328 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 21335328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36560160).

21335328 is an abundant number, since it is smaller than the sum of its proper divisors (51784992).

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

21335328 is a wasteful number, since it uses less digits than its factorization.

21335328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599 (or 588 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The square root of 21335328 is about 4619.0180774706. The cubic root of 21335328 is about 277.3531533748.

The spelling of 21335328 in words is "twenty-one million, three hundred thirty-five thousand, three hundred twenty-eight".