8. Given the sequence: $\frac{2}{3}, \frac{2}{9}, \frac{4}{9}, \frac{6}{9}, \frac{8}{9}, \frac{2}{27}, \frac{4}{27}, \cdots, \frac{26}{27}, \cdots, \frac{2}{3^{n}}, \frac{4}{3^{n}}, \cdots, \frac{3^{n}-1}{3^{n}}, \cdots$. Then $\frac{2020}{2187}$ is the \_\_\_\_ term of the sequence.
The number of terms with a denominator of 3 is 1; the number of terms with a denominator of $3^{2}$ is $\frac{3^{2}-1}{2}=4$; the number of terms with a denominator of $3^{3}$ is $\frac{3^{3}-1}{2}=13$; $\cdots$, since $2187=3^{7}$, the calculation shows that the total number of terms with denominators less than or equal to $3^{6}$ is $1+4+13+40+121+364=543$, so $\frac{2020}{2187}$ is the $543+1010=1553$-th term in the sequence.