It's more than the population of seven states: Wyoming, Vermont, North Dakota, Alaska, South Dakota, Delaware and Montana. So, if you're from one of those states, imagine if your whole population and then some were asked to leave.
Only nine cities have more than 950,000 residents. Detroit doesn't. Indianapolis, San Francisco, Austin, Boston, Seattle, Washington, D.C. and Denver aren't even close.
Only 500,000 people or so, however, are actually reported to have evacuated in California. That means that a population about the size of Cleveland or Kansas City, Missouri, has defied orders to leave.