וַיִּֽהְיוּ֙ כָּל־יְמֵי־שֵׁ֔ת שְׁתֵּ֤ים עֶשְׂרֵה֙ שָׁנָ֔ה וּתְשַׁ֥ע מֵא֖וֹת שָׁנָ֑ה וַיָּמֹֽת׃ (ס)
And all the days of Seth were nine hundred and twelve years; and he died.
Read kabbalistic (mystical) interpretation of Genesis 5:8: and classical mystical sources.