For the year 1921 two different silver dollars were issued and each is a separate series of dollar coins and the designs are very different. But because of the fact you used the motto E PLURIBUS UNUM in your question that appears on the front of the coin above Miss Liberty's head, the coin is a MORGAN dollar.
The 1921 Morgan dollar is the most common of all Morgan dollars, circulated coins run from $31.00-$40.00.
A genuine 1865 Seated Liberty silver dollar is worth no less than $300 in worn condition, and over $2,000 in uncirculated condition.
Two different types of silver dollars were struck in 1921 a Morgan Dollar and a Peace Dollar. On the front of the Morgan dollar above Liberty's head is E PLURIBUS UNUM and circulated coins are valued at $15.00-$19.00. The Peace dollar has the word Liberty above her head and circulated coins are valued at $85.00-$185.00
1899-O Liberty Silver Dollar: good condition-$11.00, mint condition-$180.00
value of an 1890 E Pluribus umun silver dollar
1899-O Liberty Silver Dollar: good condition-$11.00, mint condition-$180.00
A 1992 American Eagle Bullion Silver Dollar in MS65 condition is worth: $24.00.
Assuming it is in circulated condition, it is worth around $22.50 in silver content.
The value of coins and bills can vary greatly depending on condition and stamping. A 1995 liberty silver dollar can be worth between $20 and $100.
$60.00 to $80.00 in circulated condition.
Circulated condition $20.00 to $40.00
$13 or more depending on the condition of the coin.
A 1992 American Eagle Bullion Silver Dollar in MS65 condition is worth: $24.00.