21043224 has 24 divisors (see below), whose sum is σ = 56992260. Its totient is φ = 7014384.

The previous prime is 21043223. The next prime is 21043237. The reversal of 21043224 is 42234012.

21043224 is a `hidden beast` number, since 210 + 432 + 24 = 666.

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

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21043197 and 21043206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 146062 + ... + 146205.

Almost surely, 2^21043224 is an apocalyptic number.

21043224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21043224 is an abundant number, since it is smaller than the sum of its proper divisors (35949036).

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

21043224 is a wasteful number, since it uses less digits than its factorization.

21043224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292279 (or 292272 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 21043224 is about 4587.2893957107. The cubic root of 21043224 is about 276.0815763905.

Adding to 21043224 its reverse (42234012), we get a palindrome (63277236).

It can be divided in two parts, 2104322 and 4, that added together give a triangular number (2104326 = T₂₀₅₁).

The spelling of 21043224 in words is "twenty-one million, forty-three thousand, two hundred twenty-four".