What should I do with 600k

I came into a sum of money. I bought a house and paid off half of it. The rest is neutrally geared and just ticks away in the background. I barely even think about it. I still have around 600k cash though and would love to turn that into as much as possible of course. How much do you think I can potentially make from this? I'm 40 years old and earn around 60k a year

Before some of you say, be happy with what you have, I definitely am. I have never had money in my entire life. Quite the opposite. I just would like to set myself, and my kids up when they come along.