21536224 has 24 divisors (see below), whose sum is σ = 42689808. Its totient is φ = 10694400.

The previous prime is 21536213. The next prime is 21536261. The reversal of 21536224 is 42263512.

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 3 ways as a sum of consecutive naturals, for example, 2604 + ... + 7060.

It is an arithmetic number, because the mean of its divisors is an integer number (1778742).

Almost surely, 2^21536224 is an apocalyptic number.

It is an amenable number.

21536224 is a deficient number, since it is larger than the sum of its proper divisors (21153584).

21536224 is a wasteful number, since it uses less digits than its factorization.

21536224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4618 (or 4610 counting only the distinct ones).

The product of its digits is 2880, while the sum is 25.

The square root of 21536224 is about 4640.7137382088. The cubic root of 21536224 is about 278.2209653942.

Adding to 21536224 its reverse (42263512), we get a palindrome (63799736).

The spelling of 21536224 in words is "twenty-one million, five hundred thirty-six thousand, two hundred twenty-four".