Get date from SQL Server audit filename
This looks like number of 100 nanosecond ticks since 1601-01-01 (FILETIME)

So based on that the following works (125911584000000000 is the number of these ticks between 1601 and 2000. This is subtracted first to avoid overflowing an int)

It also looks like the time returned is UTC so you will need to convert to your local time zone (which I have made an assumption about).

DECLARE @value    BIGINT = 132327053636850000,
        @datetime DATETIME2

SELECT @datetime = DATEADD(MILLISECOND, 
                           @value%10000000 / 10000, 
                             DATEADD(SECOND, 
                             ( @value - 125911584000000000 ) / 10000000, 
                             CAST('2000-01-01' AS DATETIME2)))

SELECT CONVERT(DATETIME2(3), 
                 SWITCHOFFSET(@datetime,
                 DATEPART(TZOFFSET, @datetime AT TIME ZONE 'GMT Standard Time'))) 


Returns

2020-04-30 08:29:23.685