On September 1, 2011, Core Company's balance sheet indicates there are 600,000 shares of $30 par value common shares in the Common Stock account and $4,500,000 in the Additional Paid-in Capital account. There are 2,000,000 shares authorized. On September 2, Core splits its stock 2 for 1. How many Core's shares of common stock are issued and outstanding immediately after the stock split?