21382288 has 10 divisors (see below), whose sum is σ = 41428214. Its totient is φ = 10691136.

The previous prime is 21382271. The next prime is 21382297. The reversal of 21382288 is 88228312.

It can be written as a sum of positive squares in only one way, i.e., 20358144 + 1024144 = 4512^2 + 1012^2 .

It is a super-2 number, since 2×21382288² = 914404480229888, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 668181 + ... + 668212.

Almost surely, 2^21382288 is an apocalyptic number.

It is an amenable number.

21382288 is a deficient number, since it is larger than the sum of its proper divisors (20045926).

21382288 is a wasteful number, since it uses less digits than its factorization.

21382288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1336401 (or 1336395 counting only the distinct ones).

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

The square root of 21382288 is about 4624.0986148654. The cubic root of 21382288 is about 277.5564931111.

The spelling of 21382288 in words is "twenty-one million, three hundred eighty-two thousand, two hundred eighty-eight".