21330688 has 36 divisors (see below), whose sum is σ = 43067080. Its totient is φ = 10543104.

The previous prime is 21330679. The next prime is 21330737. The reversal of 21330688 is 88603312.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24403 + ... + 25261.

Almost surely, 2^21330688 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 21330688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21533540).

21330688 is an abundant number, since it is smaller than the sum of its proper divisors (21736392).

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

21330688 is an frugal number, since it uses more digits than its factorization.

21330688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 972 (or 958 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 21330688 is about 4618.5157789056. The cubic root of 21330688 is about 277.3330456933. Note that the first 3 decimals are identical.

The spelling of 21330688 in words is "twenty-one million, three hundred thirty thousand, six hundred eighty-eight".