As already said, the base power would be 184. However, that doesn't tell you how much damage...
The formula is:
BaseDamage = ((((2 × Level) ÷ 5 + 2) * BasePower * [Sp]Atk) ÷ [Sp]Def) ÷ 50 + 2
Plugging in your stuff...
16.8 1.2 87 /Defense/50 + 2
Damage: 35.0784/Defense+2