21243453 has 32 divisors (see below), whose sum is σ = 36191232. Its totient is φ = 10761600.

The previous prime is 21243437. The next prime is 21243473. The reversal of 21243453 is 35434212.

It is not a de Polignac number, because 21243453 - 2⁴ = 21243437 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243403) 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 31 ways as a sum of consecutive naturals, for example, 8350 + ... + 10592.

It is an arithmetic number, because the mean of its divisors is an integer number (1130976).

Almost surely, 2^21243453 is an apocalyptic number.

It is an amenable number.

21243453 is a deficient number, since it is larger than the sum of its proper divisors (14947779).

21243453 is a wasteful number, since it uses less digits than its factorization.

21243453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2305.

The product of its digits is 2880, while the sum is 24.

The square root of 21243453 is about 4609.0620520883. The cubic root of 21243453 is about 276.9544643139.

Adding to 21243453 its reverse (35434212), we get a palindrome (56677665).

The spelling of 21243453 in words is "twenty-one million, two hundred forty-three thousand, four hundred fifty-three".