It will be reachable by LAN. The gateway address is the router you use to get to addresses outside the subnet mask you set.
First search result explains it more thoroughly if you’re interested
https://www.networkcomputing.com/ip-subnetting/ip-addresses-subnet-masks-and-default-gateways

If you set the wrong gateway in the static IP settings or a reserved DHCP lease, it won’t be able to get out.