yes there is no doubt about this that bitcoin is a safe investment and that is the reason that i have invested more than my 70% assets in bitcoin.
Though bitcoin is considered safe but it is not really 100% safe, because it is a digital currency at the end no matter how strong it is or how large its community is, but it still has some demerits and price drops is one of them, but i feel believing it wont disappoint you for long run.