There is no useful universal number because GPA is interpreted in context. A 3.4 from one program may be viewed differently from a 3.4 in another, and firms also consider course rigor, work experience, leadership, office demand, and the strength of the applicant pool.
Practically, the lower the GPA goes, the more the rest of the profile needs to provide strong recent evidence. A selective internship, exceptional leadership, entrepreneurship, research, or a credible referral can all help, but none of them creates a guaranteed waiver.
Do not build your strategy around finding the lowest anecdotal GPA that ever succeeded. Instead, ask whether your total application has enough positive signals to justify an interview. If the GPA is clearly below the typical range for your school, apply broadly and strengthen every controllable part of the file.