The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 3285.4595\\[1 em]x_2 &= -9.3547+247.7536i\\[1 em]x_3 &= -9.3547-247.7536i \end{aligned} $$Polynomial $ 8x^3-26134x^2+x-1615640648 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.