21820328 has 16 divisors (see below), whose sum is σ = 41076180. Its totient is φ = 10866688.

The previous prime is 21820319. The next prime is 21820339. The reversal of 21820328 is 82302812.

It can be written as a sum of positive squares in 2 ways, for example, as 12687844 + 9132484 = 3562^2 + 3022^2 .

It is a super-2 number, since 2×21820328² = 952253428055168, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21820297 and 21820306.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3251 + ... + 7362.

Almost surely, 2^21820328 is an apocalyptic number.

It is an amenable number.

21820328 is a deficient number, since it is larger than the sum of its proper divisors (19255852).

21820328 is a wasteful number, since it uses less digits than its factorization.

21820328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10876 (or 10872 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 21820328 is about 4671.2233943583. The cubic root of 21820328 is about 279.4390470033.

The spelling of 21820328 in words is "twenty-one million, eight hundred twenty thousand, three hundred twenty-eight".