That's why I am not selling because I want to develop it and then maybe offer on flippa. Let me tell you a secret.....do not tell anyone else about it. Anyone holding 4L domains have seen their value increase over the years and with all the crazy Chinese hype about investing in numbered domains will see their investments C R A S H to earth! Just like the South Sea Bubble and similar at the start of the Internet in the late nineties. It only takes a few big investors to sell and the rest will be like lemmings jumping off the cliff.
The Chinese are short of liquidity, their economy is in turmoil, there will be a huge impact on the rest of the world. Who the hell wants a string of numbers....I don't. Stick to your short domains, develop them and you will have a solid investment to leave as a legacy for your children. Get some income from your sites (I have 600+ short domains) and you will be laughing all the way to the Moon.
It depends on how long you are willing to wait. It could sell for $1,500 to the right buyer, but you'll have to reach out to companies and individuals that may be interested. (Research on your end that can also take a lot of time). If you are trying to sell it to domainers a reasonable price would be about $250, since they would invest this in a website, resale it, or what ever they have in mind to make a profit.