Are microwaves harmful to us?
$2.45~\rm GHz$ is well into the microwave region, which is usually defined as radio waves with a frequency of greater than $1~\rm GHz$.

Microwaves can be harmful. If you stood in front of a $1~\rm MW$ microwave dish, you would be cooked basically instantly. But that doesn't mean they are harmful in small doses: if you stand in front of a $1~\rm MW$ visible light source, you would also be cooked. You can hold your hands in front of a fire, but sticking your hands in would be bad. Like heat and visible light, microwaves aren't intrinsically harmful in moderation, but they can be deadly if you have enough of them.