Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_51367 ( "Year" real, "Property Taxes" text, "Investment Earnings" text, "Other Local Sources" text, "State & Federal" text, "Total Revenue" text )

### Question ###
What were the investment earnings in a year when total revenue was $21,779,618?

### Accurate SQL ###

SELECT "Investment Earnings" FROM table_51367 WHERE "Total Revenue" = '21,779,618'