21528320 has 108 divisors (see below), whose sum is σ = 57088920. Its totient is φ = 7772160.

The previous prime is 21528319. The next prime is 21528329. The reversal of 21528320 is 2382512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21528329) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 154811 + ... + 154949.

Almost surely, 2^21528320 is an apocalyptic number.

21528320 is a gapful number since it is divisible by the number (20) 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 21528320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28544460).

21528320 is an abundant number, since it is smaller than the sum of its proper divisors (35560600).

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

21528320 is a wasteful number, since it uses less digits than its factorization.

21528320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 157 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21528320 is about 4639.8620669154. The cubic root of 21528320 is about 278.1869246451.

The spelling of 21528320 in words is "twenty-one million, five hundred twenty-eight thousand, three hundred twenty".