That's weird because its not on my list. I included a pic to show all the members it shows for me(that begin with T). It has textalign, but not text. I'm using visual studio 2008 SP1 Express Edition - if that makes any difference.
The NumericUpDown DOES have a Text property. It MUST have a Text property because it is inherited from the Control class. It is hidden from Intellisense because, as JohnH says, it's not intended to be used. That doesn't mean it can't be used though, and for this it may HAVE to be used. Consider the case where you have set the DecimalPlaces property of a NUD to 2 and the current value is 1D. The control will be displaying the string "1.00" while Value.ToString will return "1". As such you'll get the wrong length and not all the text will be selected. Just use the Text property and you'll have no issues.