Let $\Pi:=\mathbb{P}(H^0(\mathbb{P}^5,\mathcal{O}\_{\mathbb{P}}(3)))$ be the space of cubic fourfolds in $\mathbb{P}^5$. It is well-known that those cubics which are *pfaffian*, i.e. defined by the pfaffian of a 6-by-6 skew-symmetric 
matrix of linear forms, form a hypersurface in $\Pi$. Does anyone know the degree of that hypersurface?



The degree of the hypersurface of pfaffian cubic fourfolds
According to Example 3, p. 319 of 


Li, Zhiyuan; Zhang, Letao: [*Modular forms and special cubic fourfolds*](http://dx.doi.org/10.1016/j.aim.2013.06.003), Adv. Math. **245**, 315-326 (2013). [ZBL1290.11077](https://zbmath.org/?q=an:1290.11077),


the degree of $\mathcal{C}\_{14}$ should be 915678.


