21088320 has 112 divisors (see below), whose sum is σ = 73078848. Its totient is φ = 5109760.

The previous prime is 21088303. The next prime is 21088321. The reversal of 21088320 is 2388012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21088321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9562 + ... + 11558.

Almost surely, 2^21088320 is an apocalyptic number.

21088320 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 21088320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36539424).

21088320 is an abundant number, since it is smaller than the sum of its proper divisors (51990528).

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

21088320 is a wasteful number, since it uses less digits than its factorization.

21088320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2028 (or 2018 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21088320 is about 4592.2020861456. The cubic root of 21088320 is about 276.2786515740.

The spelling of 21088320 in words is "twenty-one million, eighty-eight thousand, three hundred twenty".