When can st_ino change for a direcory?

Question

I am trying to work with StructStat class in Android. As per android documentation at here

• st_ino represents File Serial Number of object
• st_blocks represents number of blocks allocated to this object

My query is

• Can st_ino which is a number, change for any directory/file, in any situation? or Would it be constant once memory is mounted.
• What does st_blocks returns, size of object means what value it has?

Thank you in advance