4. For all positive integers $n$ greater than 2, the greatest common divisor of the number $n^{5}-5 n^{3}+4 n$ is

 untranslated part:
 untranslated part remains the same as it is a mathematical expression.
4.120 .
$$
n^{5}-5 n^{3}+4 n=(n-2)(n-1) n(n+1)(n+2) \text {. }
$$

For any positive integer $n$ greater than 2, the number $n^{5}-5 n^{3}+4 n$ contains the common divisor $1 \times 2 \times 3 \times 4 \times 5=120$. Therefore, the greatest common divisor of these numbers is 120.