20830

20830 is a prime number. It is the 2351st prime number. In its decimal representation, 20830 ends in zero, making it divisible by ten. Therefore, it is not a prime number. This indicates a misunderstanding in the initial classification. Numbers ending in 0, 2, 4, 6, or 8 (except for the number 2 itself) are even and thus divisible by 2, disqualifying them from being prime. Similarly, numbers ending in 0 or 5 (except for the number 5 itself) are divisible by 5, also disqualifying them from being prime. The number 20830 falls into the category of even numbers and is also divisible by 5, making it composite. Its prime factorization is 2 x 5 x 2083. The number 2083 is itself a prime number.