I was a student learning Vedic mathematics a couple of years ago. I remember they talked about prime numbers also being mentioned in the vedas(probably Rig Veda). I tried to find links that mention it. I was only able to find a few references (might be because Vedic maths is not used outside India ?)
here. Also this link. and this for some general info on what vedic math is! Also I don't know how old they are(although Vedas are considered to be one of the oldest known texts) but I just wanted to share this!