It has been 8 years from the date Bitcoin was born. There are no known cases of hacked bitcoin. And it is impossible. But if you store Bitcoin and altcoin in hot wallet, Maybe hackers can attract it.
Yes bitcoin is providing high security. It is not easy to hack bitcoin. So its quite safe to invest here and wait for the profit patiently and be committed to what we want to do. Seek proper knowledge and be keen about guidance enter some promising project and deal the profit wisely. Then all what result will be a comfortable living.