21003208 has 16 divisors (see below), whose sum is σ = 41454000. Its totient is φ = 9948816.

The previous prime is 21003179. The next prime is 21003223. The reversal of 21003208 is 80230012.

It is a happy number.

It is a super-2 number, since 2×21003208² = 882269492582528, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21003191 and 21003200.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68938 + ... + 69241.

It is an arithmetic number, because the mean of its divisors is an integer number (2590875).

Almost surely, 2^21003208 is an apocalyptic number.

It is an amenable number.

21003208 is a deficient number, since it is larger than the sum of its proper divisors (20450792).

21003208 is a wasteful number, since it uses less digits than its factorization.

21003208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138204 (or 138200 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21003208 is about 4582.9257030853. The cubic root of 21003208 is about 275.9064655399.

The spelling of 21003208 in words is "twenty-one million, three thousand, two hundred eight".