this question just came to me and out of curiosity I decided to ask it
please list the game and number of missions
I think Hitman 2 does, with around 20. Though I might be totally wrong.
Nephys is right. The longest game in the series is Hitman 2: Silent Assassin, with 21 mission (including the prologue, The Gontranno Sanctuary). The second place goes to Hitman Absolution, with 20 missions (including the epilogue, Absolution).