  The 99942 Apophis close encounter with Earth in 2029 may provide information
about asteroid's physical characteristics and measurements of Earth's effects
on the asteroid surface. In this work, we analysed the surface and the nearby
dynamics of Apophis. The possible effects of its 2029 encounter on the surface
and environment vicinity are also analysed. We consider a 340 metres polyhedron
with a uniform density (1.29 g$\cdot$cm$^{-3}$, 2.2 g$\cdot$cm$^{-3}$ and 3.5
g$\cdot$cm$^{-3}$). The slope angles are computed, as well their variation that
arises during the close approach. Such variation reaches 4$^{\circ}$ when low
densities are used in our simulations and reaches 2$^{\circ}$ when the density
is high. The zero-velocity curves, the equilibrium points, and their
topological classification are obtained. We found four external equilibrium
points and two of them are linearly stable. We also perform numerical
simulations of bodies orbiting the asteroid, taking into account the irregular
gravitational field of Apophis and two extra scenarios of perturbations: the
solar radiation pressure and the Earth's perturbation during the close
approach. The radiation pressure plays an important role in the vicinity of the
asteroid, only cm-sized particles survived for the time of integration. For
densities of 2.2 g$\cdot$cm$^{-3}$ and 3.5 g$\cdot$cm$^{-3}$, a region of 5 cm
radius particles survived for 30 years of the simulation, and for 1.29
g$\cdot$cm$^{-3}$, only particles with 15 cm of radius survived. The ejections
and collisions are about 30-50 times larger when the close encounter effect is
added, but around 56-59% of particles still survive the encounter.
