Answer:
Mass and the type of surface.
Step-by-step explanation:
The friction that acts between two or more than two objects that are at rest with respect to each other is called static friction.
Mathematically, it can be written as :

Where,
is the coefficient of static friction.
m is the mas of an object
g is the acceleration due to gravity.
So, from above equation it is clear that the static friction between two surfaces increase with the increase of mass and the roughness of the surface.