Please check your bill again and post a new question. The US didn't issue any bills with that date, and the last $20 silver certificates were dated 1891.
1921 is by far the most common date for Morgan silver dollars. At current silver prices, one is worth about $23.
Not a Morgan dollar, last year was 1921. You have a 1923 Peace dollar that is very common and has values of $25.00-$27.00 in circulated condition.
The last year for Morgan dollars was 1921.If you have a Peace dollar from 1924, see the Related Question for more information.
The coin has no numismatic value, it is considered altered because of the coloring which destroys the collectible value of any coin. Value is only for the silver, that today is about $22.00.
For the series of Morgan dollars 1921 is the most common highest mintage year. Assuming the coin is circulated and depending on grade a 1921-D retails at $16.00-$25.00
The intrinsic value is $14.16 with silver at $18.31 per ounce
1922 silver dollar with closed eagle wings
A 1921 Half Dollar is 90% silver. It has a melt value of somewhere around $12. The related link below has more information.
Please see:
The '21 Morgan and '22 Peace are the most common years for those designs, usually selling for around $20-$30 each. The certificate value depends on series year, though anything dated 1935 or 1957 is typically only worth $2 or so. Then with the granules, value depends on weight and purity.
Assuming it's a more common Morgan dollar, about $13 for its silver content
Please see Related Answers:
There is around .77 ounces in a 1921 US silver dollar.
There's a Peace dollar but not a war dollar. Please see the Related Question.
A average Mint State 1921 Morgan is $30.00-$40.00
1921 is by far the most common date for Morgan dollars -- current value is about $17.00
There were no $1 silver certificates printed with that date. If you're referring to a $1 coin, please post a new question. Indicate how worn the coin is, and whether there is a small letter (D or S) under the eagle on the back side of the coin.