"Isitvam" is the power to create. That is why we have God Iswaran." Prakamyam" is the power of disembodiment. Can we do this? Adishankara did this to answer a question raised by MandanaMisrar as to what family life is. There is an ultimate sidhdhi which is the resultant of all these
'Isithavam' The sidhdhas have the creative power of God and control over the Sun, the moon and the elements. All the three Tevara muvar had this. Gnana Sambandar gave life to Angam Poompavai. Sundarar got back the son for the parents at Avinashi after five years of his death. Appar brought back to life Appudi Adigal's son. Many such examples may be cited
"Prapti"- This sidhdhi actually means, you can get anything you want under the sun. It also means the capacity to reach any place at any time that you desire. Can we obtain this? Is it possible? All these questions arise. Anjaneya reached Himalayas and brought Sanjeevi Parvadam for the sake of Rama. It is attainable. But the ways are secretive.
Vasithavam-It means domination over People and things. It is the power to attract anybody and everybody whom you like. This has to be used only for right causes. Some people are always attractive in whatever they say and do. It is because they have practiced this in their previous birth. The power is attained to the extent of practice
"Bhukti" is the sidhdhi which is attainable, after attaining all the sidhdhis. It is nothing but reaching the Go. Now, to attain the sidhdhis there very specific ways and means.