What is the value of a 1641 US quarter?

Check your dates again. The United States did not exist until after the Revolutionary War, which is though to have begun with the Declaration of Independence in 1776. Any coin dated 1641 therefore is 135 years older than the US and cannot be a US coin.

Also note, with all coin collection, the condition of the coin is as important as the age or rarity. Collectors like to collect coins that are in good condition. So the age along will not tell you the value of the coin. But any coin that is actually from the year 1641 would have some value.