A number when increased by 50%’,

Let the number be $x$.
$ x + 50% \text{ of } x = 2580 $
$ x + \frac{50}{100}x = 2580 $
$ x + 0.5x = 2580 $
$ 1.5x = 2580 $
$ x = \frac{2580}{1.5} = 1720 $
Answer: 1720