A hiker traveled an average of 900 miles in 36 days. One day, he increases his daily average to 16 miles. This reduces his remaining journey by a certain number of days. After that, he finds a shortcut which saves him an additional 4 days, and a friendly traveller advised him of another path that will save him 40 days. If he also saves 21 days due to good weather, how many days in total did he save on his journey?