21607328 has 48 divisors (see below), whose sum is σ = 44706816. Its totient is φ = 10268160.

The previous prime is 21607321. The next prime is 21607361. The reversal of 21607328 is 82370612.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21607328.

It is not an unprimeable number, because it can be changed into a prime (21607321) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 56225 + ... + 56607.

It is an arithmetic number, because the mean of its divisors is an integer number (931392).

Almost surely, 2^21607328 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 21607328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22353408).

21607328 is an abundant number, since it is smaller than the sum of its proper divisors (23099488).

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

21607328 is a wasteful number, since it uses less digits than its factorization.

21607328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 477 (or 469 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 21607328 is about 4648.3683158717. The cubic root of 21607328 is about 278.5268204957.

The spelling of 21607328 in words is "twenty-one million, six hundred seven thousand, three hundred twenty-eight".