Response to the following problem:
Lowly Worm Corporation's common share price is currently around $5 per share. The board of directors have decided that a more respectable share price level is around $20. The board also realizes that in the company's current circumstance, share price is not expected to increase and cannot be increased other than with a reverse stock split. What size reverse split is necessary to increase the share price to the desirable level?
Show all work and calculations.