450

450 is just an estimate as there is no sources which list dates for these people they are semi mythical

In addition to what Jason said, you'll start to notice that most pre-High Middle Ages profiles give rounded, estimated dates in their timelines. (A lot of people seem to go in 30- or 50-year increments.) This is typical of most characters from myth. You'll also note the curator note on that profile stating that most of his "children" probably weren't his anyway, making genealogical connections to him (if he really existed as represented) tenuous at best.

If you're going to take mythological and Biblical "genealogy" seriously, you'll get used to encountering this a lot. The farther back you go, the less realistic most of it is, sadly enough.