Quinque is actually cognate with English five. This may seem a bit strange, but P and Kw are common developments between different Indo-European languages.
Indo-European 'pénkwe' = Latin 'quinque' (Proto-Italic 'kwenkwe'), and Proto-Germanic 'fimf' (Pre-Proto-Germanic 'pimpe').
In English the Ingvaeonic Nasal Spirant Law means that nasal sounds are lost before fricatives (-nth, -ns, -nf), thereby lengthening the vowel (Old English fīf, modern five), whereas in Scandinavian languages the fricative is lost, but the nasal is doubled (Old Norse fimm), while German keeps both (fünf).
The same can be seen in Four (kwetwóres > quattuor = kwetwōr > petwōr, fedwōr > fēowor > four)