21303208 has 8 divisors (see below), whose sum is σ = 39943530. Its totient is φ = 10651600.

The previous prime is 21303203. The next prime is 21303209. The reversal of 21303208 is 80230312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21141604 + 161604 = 4598^2 + 402^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21303203) by changing a digit.

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 as a sum of consecutive naturals, namely, 1331443 + ... + 1331458.

Almost surely, 2^21303208 is an apocalyptic number.

It is an amenable number.

21303208 is a deficient number, since it is larger than the sum of its proper divisors (18640322).

21303208 is a wasteful number, since it uses less digits than its factorization.

21303208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2662907 (or 2662903 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21303208 is about 4615.5398384154. The cubic root of 21303208 is about 277.2138998699.

The spelling of 21303208 in words is "twenty-one million, three hundred three thousand, two hundred eight".