Good at remembering:
— A retentive mind.

synonyms: long, recollective, tenacious.

Roget 781: retaining etc. v.; retentive, tenacious.    unforfeited^†, undeprived, undisposed, uncommunicated.    incommunicable, inalienable; in mortmain [Fr.]; in strict settlement.   

Having the capacity to retain something.

Polish: retencyjny

Having the power, capacity, or quality of retaining water.