Help Formatting Numbers in Formulas

Power Query

let
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    #"Split Column by Delimiter" = Table.SplitColumn(Source,"Column1",Splitter.SplitTextByDelimiter("_", QuoteStyle.Csv),{"Column1.1", "Column1.2", "Column1.3"}),
    #"Removed Columns" = Table.RemoveColumns(#"Split Column by Delimiter",{"Column1.1"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Removed Columns",{{"Column1.2", type date}, {"Column1.3", Int64.Type}})
in
    #"Changed Type"