  The Rosetta mission of the European Space Agency has been orbiting the comet
67P/Churyumov-Gerasimenko (67P) since August 2014 and is now in its escort
phase. A large complement of scientific experiments designed to complete the
most detailed study of a comet ever attempted are onboard Rosetta. We present
results for the photometric and spectrophotometric properties of the nucleus of
67P derived from the OSIRIS imaging system, which consists of a Wide Angle
Camera (WAC) and a Narrow Angle Camera (NAC). The disk-averaged phase function
of the nucleus of 67P shows a strong opposition surge with a G parameter value
of -0.13$\pm$0.01 in the HG system formalism and an absolute magnitude
$H_v(1,1,0)$ = 15.74$\pm$0.02 mag. The integrated spectrophotometry in 20
filters covering the 250-1000 nm wavelength range shows a red spectral
behavior, without clear absorption bands except for a potential absorption
centered at $\sim$ 290 nm that is possibly due to SO$_2$ ice. The nucleus shows
strong phase reddening, with disk-averaged spectral slopes increasing from
11\%/(100 nm) to 16\%/(100 nm) in the 1.3$^{\circ}$--54$^{\circ}$ phase angle
range. The geometric albedo of the comet is 6.5$\pm$0.2\% at 649 nm, with local
variations of up to $\sim$ 16\% in the Hapi region. From the disk-resolved
images we computed the spectral slope together with local spectrophotometry and
identified three distinct groups of regions (blue, moderately red, and red).
The Hapi region is the brightest, the bluest in term of spectral slope, and the
most active surface on the comet. Local spectrophotometry shows an enhancement
of the flux in the 700-750 nm that is associated with coma emissions.
