How to convert json.Number to int64

Hello, I’m getting a json response and using unmarshal to get a timestamp that comes in the json response. Now i need to get that timestamp and divide it. In the comments in a stackoverflow post they say to use json.Number.int64. I’m new to go and don’t know what to do. I tried this
token.ExpiresOnTimestamp.Int64()
fmt.Println(" -string ", token),
but know what else to do.

What do you mean with that?
Can you give us an example of the data you receive and the expected results?