Characters allowed after a bigint

1337n⟦09⟧in alert(9)

1337n
in alert(10)

1337n0x0Bin alert(11)

1337n0x0Cin alert(12)

1337n
in alert(13)

1337n in alert(32)

1337n in alert(160)

1337n in alert(5760)

1337n in alert(8192)

1337n in alert(8193)

1337n in alert(8194)

1337n in alert(8195)

1337n in alert(8196)

1337n in alert(8197)

1337n in alert(8198)

1337n in alert(8199)

1337n in alert(8200)

1337n in alert(8201)

1337n in alert(8202)

1337n
in alert(8232)