Sorry for the loss that led to this inheritance!
It might be too late for this if the money is already in your possession, but you should consider whether you want to put this in an account with your husband's name on it. It's usually something people don't want to consider, thinking it won't happen to them, but that includes the large number if couples who get divorced, so you never know. This is your inheritance, so as long as you don't "commingle" it with marital finances, it won't be among the assets split in the event of divorce. If it is commingled (but sending it through an account that you both own) then it will be split. Just something to think about. If you're fine taking that risk, then that's fine, just take it with your eyes open.
https://www.bogleheads.org/wiki/Managing_a_windfall would be worth reading.
I'm not sure where you saw the advice to put an inheritance in a 529, but I would place that account towards the end of the priorities. Any future children can borrow to fund their education, you can't borrow to fund retirement.
There's nothing inherently different about money from an inheritance than money from anything else, so I would suggest putting it in accounts in the order recommended here:
https://forum.mrmoneymustache.com/investor-alley/investment-order/msg1333153/#msg1333153. Obviously you can't put it directly into a 401(k), but if you can't otherwise contribute the max to your 401(k) you could up your payroll deductions "too much" and live off the inheritance to make up the difference. This would be counter to keeping the inheritance separate from marital assets, so make that decision first. If you don't want to split the inheritance in the event of divorce, ignore the investment order and put it straight into a taxable account in your name only and keep it there.
As far as what do invest in
https://www.bogleheads.org/wiki/Asset_allocation would be worth a read to get a broad sense. Once you know what asset classes you want to invest in and in what amounts you can come back here for advice on particular investments based on the company you choose to invest with. Vanguard, Fidelity, Schwab, Etrade, and TD Ameritrade would be my suggestions, probably in that order, with possible variation depending if you or your husband wants to open a self employed retirement plan.