Love him or hate him like I do, Trump is undeniably charismatic. When I saw him in person at a rally early in the 2016 campaign (I initially went for the lols), I walked out knowing that this guy was a legitimate contender for the presidency then.
As always, I think 'charismatic' is not quite the right word. Trump inspires as much revulsion as adulation. His presence is polarizing - few people walk away from Trump saying, "I really disagree with him, but he seems like a good person." Trump appeals to those drawn to evil, and weak-minded fools. He is a vile and persuasive huckster, but I think Obama, W, and Clinton all had far more charisma than he does.
