Is zakat obligatory on a large amount of money acquired through haram means, such as selling alcohol, promoting music, or dealing drugs?

Unlawful wealth is not subject to zakat, nor is zakat valid for it, because it is not owned by the one who possesses it, and ownership is a condition for zakat. Allah is good and accepts only what is good. The obligation is to dispose of unlawful wealth by returning it to its rightful owners if possible. Otherwise, it should be spent on various charitable causes with the intention of getting rid of it, not as an act of charity. Unlawful wealth is not purified by giving it out. This is agreed upon by the four schools of thought: there is no zakat, no Hajj, and no financial expiation on purely unlawful wealth. Furthermore, the legal dispositions of the usurper concerning usurped wealth are not valid.