21567216 has 40 divisors (see below), whose sum is σ = 60781824. Its totient is φ = 6535360.

The previous prime is 21567191. The next prime is 21567229. The reversal of 21567216 is 61276512.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 19896 + ... + 20951.

Almost surely, 2^21567216 is an apocalyptic number.

It is an amenable number.

21567216 is an abundant number, since it is smaller than the sum of its proper divisors (39214608).

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

21567216 is a wasteful number, since it uses less digits than its factorization.

21567216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40869 (or 40863 counting only the distinct ones).

The product of its digits is 5040, while the sum is 30.

The square root of 21567216 is about 4644.0516792990. The cubic root of 21567216 is about 278.3543606649.

The spelling of 21567216 in words is "twenty-one million, five hundred sixty-seven thousand, two hundred sixteen".