21328710 has 64 divisors (see below), whose sum is σ = 58387392. Its totient is φ = 4939776.

The previous prime is 21328673. The next prime is 21328729. The reversal of 21328710 is 1782312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5022 + ... + 8238.

It is an arithmetic number, because the mean of its divisors is an integer number (912303).

Almost surely, 2^21328710 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21328710, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29193696).

21328710 is an abundant number, since it is smaller than the sum of its proper divisors (37058682).

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

21328710 is a wasteful number, since it uses less digits than its factorization.

21328710 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3257.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21328710 is about 4618.3016358830. The cubic root of 21328710 is about 277.3244730409.

The spelling of 21328710 in words is "twenty-one million, three hundred twenty-eight thousand, seven hundred ten".