21328288 has 24 divisors (see below), whose sum is σ = 42097860. Its totient is φ = 10636800.

The previous prime is 21328283. The next prime is 21328289. The reversal of 21328288 is 88282312.

21328288 is nontrivially palindromic in base 14.

It can be written as a sum of positive squares in 2 ways, for example, as 20903184 + 425104 = 4572^2 + 652^2 .

It is not an unprimeable number, because it can be changed into a prime (21328283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18678 + ... + 19786.

Almost surely, 2^21328288 is an apocalyptic number.

It is an amenable number.

21328288 is a deficient number, since it is larger than the sum of its proper divisors (20769572).

21328288 is a wasteful number, since it uses less digits than its factorization.

21328288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1720 (or 1712 counting only the distinct ones).

The product of its digits is 12288, while the sum is 34.

The square root of 21328288 is about 4618.2559478660. The cubic root of 21328288 is about 277.3226440242.

The spelling of 21328288 in words is "twenty-one million, three hundred twenty-eight thousand, two hundred eighty-eight".