Long Integer
From The Elder Scrolls Construction Set Wiki
Long is an integer format that uses 32 bit for data. The highest bit is the sign, so the variable ranges from -2^31 (-2147483648) to 2^31-1 (2147483647).
However, in Oblivion, all longs are actually stored as floats, so they experience the same limitations as floats, and so cannot actually reach the ranges that a long should be able to reach (see the float article for more information on float's limitations; see the Discussion here for information on how this was discovered).
