21552224 has 24 divisors (see below), whose sum is σ = 43468488. Its totient is φ = 10512640.

The previous prime is 21552221. The next prime is 21552233. The reversal of 21552224 is 42225512.

It is a self number, because there is not a number n which added to its sum of digits gives 21552224.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21552221) 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, 6902 + ... + 9525.

It is an arithmetic number, because the mean of its divisors is an integer number (1811187).

Almost surely, 2^21552224 is an apocalyptic number.

It is an amenable number.

21552224 is an abundant number, since it is smaller than the sum of its proper divisors (21916264).

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

21552224 is a wasteful number, since it uses less digits than its factorization.

21552224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16478 (or 16470 counting only the distinct ones).

The product of its digits is 1600, while the sum is 23.

The square root of 21552224 is about 4642.4372909066. The cubic root of 21552224 is about 278.2898483067.

Adding to 21552224 its reverse (42225512), we get a palindrome (63777736).

The spelling of 21552224 in words is "twenty-one million, five hundred fifty-two thousand, two hundred twenty-four".