Here is an image showing the pin diagram of this transistor.
Classification of hFE
The KTD998-R transistor can have a current gain of 55 to 110. The gain of the KTD998 will be in the range from 55 to 160, for the KTD998-O it will be in the range from 80 to 160.
Complementary PNP transistor
The complementary PNP transistor to the KTD998-R is the KTB778-R.
Replacement and Equivalent for KTD998-R transistor