Simplify the following expression:
$$9^{18}÷3^{14}\text{ of }27^3\times \sqrt{6561}$$

According to the BODMAS rule, the operations must be performed in the order of Brackets, Orders (Powers/Roots), "Of", Division, Multiplication, Addition, and Subtraction.
Let's convert all terms to a common base of $3$:

1. $9^{18}=(3^2{)}^{18}=3^{36}$
2. $27^3=(3^3{)}^3=3^9$
3. $\sqrt{6561}=81=3^4$

Substitute these base-$3$ values back into the expression:

$$\text{Expression}=3^{36}÷3^{14}\text{ of }{3}^9\times 3^4$$

Step 1: Solve the 'of' operation:

$$3^{14}\text{ of }{3}^9=3^{14}\times 3^9=3^{14+9}=3^{23}$$

Now the expression is:

$$3^{36}÷3^{23}\times 3^4$$

Step 2: Solve the division operation:

$$3^{36}÷3^{23}=3^{36-23}=3^{13}$$

Now the expression is:

$$3^{13}\times 3^4$$

Step 3: Solve the multiplication operation:

$$3^{13}\times 3^4=3^{13+4}=3^{17}$$

Therefore, the simplified value is $3^{17}$.