The 924e already has 24 analog FXS ports. If you have access to the configuration or your vendor is willing to set it up for you, you can just associate those ports with your incoming numbers and skip the need for PRI.
If that's not practical, you can use a 624 but you'll need a DSX model.
You don't need the 624. The TA924e has the same 24 FXS ports as a 624. It can natively deliver 24 analog ports from a SIP carrier handoff, a PRI carrier handoff, or both.