The converse of this result, namely that every even perfect number is of the form 2k-1(2k - 1) where 2k - 1 is prime, was proved by Euler . Rashed (, or) claims that ibn al-Haytham was the first to state this converse (although the statement does not appear explicitly in ibn al-Haytham's work).
Ang pag-usapan ng mga ito dito, namely na ang bawat kahit perfect number ay ang form ng 2 k -1 (2 k - 1) kung saan 2 k - 1 ay kalakasan, ay proved by Euler. Rashed (, o) claims na Ibn al-Haytham ay ang unang estado upang pag-usapan ito (bagama't ang mga pahayag ay hindi lilitaw sa explicitly Ibn al-Haytham ng trabaho).