21204453 has 8 divisors (see below), whose sum is σ = 28300768. Its totient is φ = 14122224.

The previous prime is 21204451. The next prime is 21204487. The reversal of 21204453 is 35440212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21204453 - 2¹ = 21204451 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 726 + ... + 6552.

It is an arithmetic number, because the mean of its divisors is an integer number (3537596).

Almost surely, 2^21204453 is an apocalyptic number.

It is an amenable number.

21204453 is a deficient number, since it is larger than the sum of its proper divisors (7096315).

21204453 is a wasteful number, since it uses less digits than its factorization.

21204453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7043.

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

The square root of 21204453 is about 4604.8293127976. The cubic root of 21204453 is about 276.7848773090.

Adding to 21204453 its reverse (35440212), we get a palindrome (56644665).

The spelling of 21204453 in words is "twenty-one million, two hundred four thousand, four hundred fifty-three".