Here are some of the factors that can affect the value of a 1921 silver dollar:
* Condition: The condition of a coin is one of the most important factors in determining its value. Coins that are in mint condition (also known as "uncirculated") are worth more than coins that have been circulated and show signs of wear.
* Rarity: The rarity of a coin also plays a role in its value. Some 1921 silver dollars are more rare than others, and these coins can command a higher price.
* Errors and varieties: Errors and varieties are coins that have been struck with an error or deviation from the normal design. These coins can be very valuable, especially if they are rare.
If you have a 1921 silver dollar, you can estimate its value by doing some research online or by consulting with a coin dealer.