You can make 177 valid words from the letters in ACEKPST using the Scrabble US/CAN dictionary.
How many points is ACEKPST worth in Scrabble?
ACEKPST is worth 15 points in Scrabble (US/CAN) and 17 points in Words With Friends.
How do I use the Word Unscrambler tool?
Enter any letters into the input box and press Search. The tool will return every valid English word that can be made from those letters using the dictionary you select.