21824216 has 8 divisors (see below), whose sum is σ = 40920420. Its totient is φ = 10912104.

The previous prime is 21824203. The next prime is 21824221. The reversal of 21824216 is 61242812.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1364006 + ... + 1364021.

Almost surely, 2^21824216 is an apocalyptic number.

It is an amenable number.

21824216 is a deficient number, since it is larger than the sum of its proper divisors (19096204).

21824216 is a wasteful number, since it uses less digits than its factorization.

21824216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2728033 (or 2728029 counting only the distinct ones).

The product of its digits is 1536, while the sum is 26.

The square root of 21824216 is about 4671.6395408893. The cubic root of 21824216 is about 279.4556430644.

The spelling of 21824216 in words is "twenty-one million, eight hundred twenty-four thousand, two hundred sixteen".