Your number seems to be the number of microseconds since 1970 (unix time) rather than q's usual epoch of 2000. The tok that you're using only natively supports these for 9 to 11 digits and assumes seconds.
This answer is the same as Seans, (and less succinct!), but just to add that sometimes it can be helpful to explicitly multiply your number by a microsecond given that your number is a count of microseconds, i.e.
Often makes it easier to read and makes it clearer what's happening.