Zephyr Enterprise API - date conversions

Hi I am currently processing json responses from the Zephyr API and have been running into dates in the responses that I am not sure how to convert to mm/dd/yyyy

for instance an excerpt from a test case json response..

{...

  "lastModifiedOn": 1646751423000

..}

is there a basic math process I can run on those dates to convert them to human readable mm/dd/yyyy