The sum of the interior angles of a polygon can be calculated using the formula:
\[ \text{Sum of interior angles} = (n - 2) \times 180° \]
where \( n \) is the number of sides in the polygon.
For a 33-sided polygon:
\[ \text{Sum of interior angles} = (33 - 2) \times 180° = 31 \times 180° \]
Now, calculate \( 31 \times 180 \):
\[ 31 \times 180 = 5580° \]
Therefore, the sum of all interior angles of a 33-sided regular polygon is \( \boxed{5580°} \).