Can we block routes/traffic using the AS number/AS path?

The AS is the router in the internet and there is no direct/indirect BGP peering with the device/AS.

No, we cannot configure any criteria if there is no Direct/Indirect BGP peering. A BGP peering is necessary for this.

If a direct/indirect BGP peering is present, we can configure the BGP to reject the routes as below:

set policy-options policy-statement reject-some-routes term find-routes from as-path orig-in-64513
set policy-options policy-statement reject-some-routes term find-routes from as-path orig-in-64514
set policy-options policy-statement reject-some-routes term find-routes then reject

Reference - https://www.juniper.net/documentation/us/en/software/junos/routing-policy/topics/example/policy-as-path-regular-expressions.html