Electrophotographic photoreceptor and image forming apparatus

Electrophotographic photoreceptor including a conductive substrate, an organic photosensitive layer on an outer peripheral surface of the conductive substrate, and an inorganic protective layer on an outer peripheral surface of the organic photosensitive layer, the inorganic protective layer containing gallium and oxygen. A volume resistivity of an inner region of the inorganic protective layer, the inner region extending 0.2 μm or about 0.2 μm from an inner peripheral surface of the inorganic protective layer in a thickness direction, and a volume resistivity of an outer region of the inorganic protective layer, the outer region extending 0.2 μm or about 0.2 μm from an outer peripheral surface of the inorganic protective layer in the thickness direction, are both 6.0×107 Ω·cm or more and 4.0×108 Ω·cm or less or about 6.0×107 Ω·cm or more and about 4.0×108 Ω·cm or less.