21447208 has 16 divisors (see below), whose sum is σ = 40896000. Its totient is φ = 10541616.

The previous prime is 21447203. The next prime is 21447229. The reversal of 21447208 is 80274412.

It is not an unprimeable number, because it can be changed into a prime (21447203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22248 + ... + 23191.

It is an arithmetic number, because the mean of its divisors is an integer number (2556000).

Almost surely, 2^21447208 is an apocalyptic number.

It is an amenable number.

21447208 is a deficient number, since it is larger than the sum of its proper divisors (19448792).

21447208 is a wasteful number, since it uses less digits than its factorization.

21447208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45504 (or 45500 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 21447208 is about 4631.1130411598. The cubic root of 21447208 is about 277.8371110707.

The spelling of 21447208 in words is "twenty-one million, four hundred forty-seven thousand, two hundred eight".