21303228 has 12 divisors (see below), whose sum is σ = 49707560. Its totient is φ = 7101072.

The previous prime is 21303209. The next prime is 21303229. The reversal of 21303228 is 82230312.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21303229) by changing a digit.

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, 887623 + ... + 887646.

Almost surely, 2^21303228 is an apocalyptic number.

It is an amenable number.

21303228 is an abundant number, since it is smaller than the sum of its proper divisors (28404332).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21303228 is a wasteful number, since it uses less digits than its factorization.

21303228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1775276 (or 1775274 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21303228 is about 4615.5420050087. The cubic root of 21303228 is about 277.2139866217.

The spelling of 21303228 in words is "twenty-one million, three hundred three thousand, two hundred twenty-eight".