Emergency funds are a relative thing. I know we all like the 6 months of expenses rule. But I feel like their are some caveats to that. If you have liquid investments, while it's not ideal, that does give you more flexibility in case something happens. If you don't own a property you have less likelihood of a major repair, same if you don't own a car or own a car under full warranty.
But in your case, you own two properties, probably have little access to additional low interest credit and no liquid investments, so 21K still sounds quite low to me for an emergency fund. I would think 6 months living expenses, plus 10K per property would be the baseline I would go with.