Binomial Theorem

Let \(\alpha\) be the constant term in the binomial expansion of \(\left(\sqrt{x}-\frac{6}{x^{\frac{3}{2}}}\right)^{n}, n \leq 15\). If the sum of the coefficients of the remaining terms in the expansion is 649 and the coefficient of \(x^{-n}\) is \(\lambda \alpha\), then \(\lambda\) is equal to _____________.