21352224 has 24 divisors (see below), whose sum is σ = 56049840. Its totient is φ = 7117376.

The previous prime is 21352223. The next prime is 21352229. The reversal of 21352224 is 42225312.

It is a tau number, because it is divible by the number of its divisors (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21352224.

It is not an unprimeable number, because it can be changed into a prime (21352223) by changing a digit.

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, 111114 + ... + 111305.

It is an arithmetic number, because the mean of its divisors is an integer number (2335410).

Almost surely, 2^21352224 is an apocalyptic number.

21352224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21352224 is an abundant number, since it is smaller than the sum of its proper divisors (34697616).

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

21352224 is a wasteful number, since it uses less digits than its factorization.

21352224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222432 (or 222424 counting only the distinct ones).

The product of its digits is 960, while the sum is 21.

The square root of 21352224 is about 4620.8466756645. The cubic root of 21352224 is about 277.4263484434.

Adding to 21352224 its reverse (42225312), we get a palindrome (63577536).

The spelling of 21352224 in words is "twenty-one million, three hundred fifty-two thousand, two hundred twenty-four".