On January 1, 2017, Sandhill Manufacturers had 525,000 common shares outstanding. On April 1, the corporation issued 52,500 new common shares to raise additional capital. On July 1, the corporation declared and distributed a 10% stock dividend on its common shares. On November 1, the corporation repurchased on the market 8,000 of its own outstanding common shares to make them available for issuances related to its key executives outstanding stock options.

Calculate the weighted average number of shares outstanding as at December 31, 2017.