Agreed with other answer. The one thing I would add is that a skill that is critical on the job is what I would call "number sensitivity" for a lack of better description. This skill straddles between the domains of math, memory and business judgement.
At its essence "number sensitivy" it's the ability of the consultant to understand the relevancy/importance of a number very quickly (e.g. during a conversation, within the first 5-10 seconds s/he looks at a document) and therefore being able to ask follow up questions on it in the moment and find the root cause of an issue more efficiently. To do this the consultant usually needs to have the following:
-very good memory of all relevant client, competitor, adjacent industry key metrics
-ability to do simple math in his/her head quickly
-good business judgment to understand whether that number might be (or not be) the culprit of problem at hand
To give an example: if during week zero of a case during interviews with the executive team one of the interviewees says that in their product development team 10 people out of 30 left in the last 12 months, the consultant should be able to discern whether this is a ratio that is in the norm or is high or low and asks follow up questions on it if relevant or move on to other insights. Average consultant would take note and come back to it later once s/he does the research and understands the relevancy of that number.