two to three weeks
The ear canals should have completely opened by now and he will be able to hear all the household sounds. If he is a pure white kitten and you notice he does not respond to sounds, he could be deaf. This is not a handicap or a hardship, it just happens. Deaf kitties are a delight, as they are friendly and fearless!
The kitten is more aware of his surroundings and will start to explore his box. He is able to purr and can stand up and walk a short distance. Baby teeth will start to appear. At the end of the third week, the kitten eyes will begin to change to their permanent color. Also, he will begin to eliminate on his own, without having to be stimulated.
The kitten is ready for socialization and can be introduced to other people and animals, as long as they are healthy.