21248320 has 56 divisors (see below), whose sum is σ = 52815744. Its totient is φ = 8126976.

The previous prime is 21248309. The next prime is 21248363. The reversal of 21248320 is 2384212.

21248320 is nontrivially palindromic in base 14.

It is a super-2 number, since 2×21248320² = 902982205644800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21248291 and 21248300.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5917 + ... + 8803.

Almost surely, 2^21248320 is an apocalyptic number.

21248320 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 21248320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26407872).

21248320 is an abundant number, since it is smaller than the sum of its proper divisors (31567424).

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

21248320 is a wasteful number, since it uses less digits than its factorization.

21248320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2927 (or 2917 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 21248320 is about 4609.5900034602. The cubic root of 21248320 is about 276.9756133309.

The spelling of 21248320 in words is "twenty-one million, two hundred forty-eight thousand, three hundred twenty".