What does 3.54k means?

Answer 1

3.54k is the same as writing 3,540 The format 3.54k is often used for writing usually very large numbers, because it saves space. For example, writing 2.5m takes less space than writing 2,500,000

Answer 2

In computing it could mean 3.54*2^10 = 3.54*1024 = 3624.96 In other contexts it is 3.54*1000 = 3540.