6. Among the numbers $1,2, \cdots, 2005$, what is the minimum number of numbers that need to be removed so that in the remaining numbers, no number is equal to the product of any two other numbers?
(Cue: Strike out the 43 numbers $2,3, \cdots, 44$. Among the remaining numbers (excluding 1), the product of any two numbers is greater than $45^{2}=2025>2005$. Also, for the following 43 triples:
$$
(2,87,2 \times 87),(3,86,3 \times 86), \cdots,(44,45,44 \times 45),
$$

these 129 numbers are all distinct, greater than 1, and less than 2005, so at least 43 numbers must be struck out.)