Definition:Perfect Number/Historical Note/Mistake 1

Source Work

 * The Dictionary
 * $28$
 * $28$

Mistake

 * The first $4$ perfect numbers, $6$, $28$, $496$ and $8218$, were known to the late Greeks.

That last number should be $8128$.

Interestingly and oddly, this is correct in the first edition of of $1986$.