21200243 has 4 divisors (see below), whose sum is σ = 21651360. Its totient is φ = 20749128.

The previous prime is 21200233. The next prime is 21200279. The reversal of 21200243 is 34200212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21200243 - 2¹⁰ = 21199219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21200233) 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, 225488 + ... + 225581.

It is an arithmetic number, because the mean of its divisors is an integer number (5412840).

Almost surely, 2^21200243 is an apocalyptic number.

21200243 is a deficient number, since it is larger than the sum of its proper divisors (451117).

21200243 is an equidigital number, since it uses as much as digits as its factorization.

21200243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451116.

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 21200243 is about 4604.3721613267. The cubic root of 21200243 is about 276.7665581779.

Adding to 21200243 its reverse (34200212), we get a palindrome (55400455).

The spelling of 21200243 in words is "twenty-one million, two hundred thousand, two hundred forty-three".