Nobody can really tell. There are an estimated 100,000,000,000,000,000,000 (100 quintrillion) probably more.
Of those it's estimated to be about 3,000,000,000,000,000 (3 thousand trillion) will be hypergiants.
There are about 2,500 stars visible to the naked eye at any one point at any one time on the Earth, and 5,800-8,000 total visible stars. But this is a very tiny fraction of the stars the Milky Way is thought to have! Astronomers estimate that there are 200 billion to 400 billion stars contained within the Milky Way.
Relatively few, at least if you consider it as a percentage of all the stars. Many stars will eventually become red giants, but since this is a stage that only lasts a few million years - a short time in the lifetime of a star - at any one moment only a small proportion of the stars are red giants. Sorry, I couldn't get more precise data, such as percentages. On the other hand, there are many red giants in almost any galaxy, and there are billions of galaxies in the observable Universe; that makes for a fairly large number of red giants (if considered in absolute terms, as opposed to a percentage of the star population).
If you mean things like a red giant then the answer in infinite. A red giant forms when the star is about to die and it expands almost engulfing its whole solar system of plants if it has one. Our sun will do this. After the sun dies down it becomes a white dwarf and very small. But if the star is already very big, a supernova occurs and the star exploded and briefly becomes the brightest thing in the universe that we know of.
There are many giant stars. Some of the most well known are:
Present knowledge indicates that the sun is a second generation star and that there are some thrid generation stars in the universe.
They are red giants.
Stars become Red Giants when the main sequence ends in a star which can be different periods of time depend on if it is a high-massive star or a low-massive star. :)
Red giants. By the way, what if it was a white star.
Red Giants and black holes
the red giant phase is about the end of a stars life. it will last for about one million years.
Yes red giants are the largest. But the bigger stars of red giants can be called red hyper giants.
Yes. The lowest mass stars are red dwarfs while many older stars turn into red giants and red supergiants.
No, they are mostly red dwarf stars.
The large hot stars are typically called "blue-white" stars or also Blue Giants. Cooler large stars are called Red Giants.
If they have red stars including giants in, they can't be all that featureless.
Most medium mass stars such as our Sun DO become red giants. Smaller stars do not have enough mass to initiate helium fusion when the hydrogen supply begins to run low, and do not become red giants.
All stars eventually turn into Red Giants or Super Giants
I think you are referring to red giants.
No, red giants are generally older than main sequence stars, as red giants have no hydrogen left for fuel, and burn helium instead. where as Main Sequence stars burn hydrogen for fuel.
Yes, there are. The classic red giants that come from sun- like stars, and red supergiants come from blue giants.
With red giants and main sequence stars they are not entirely featureless, therefore there is no name for them.
Red giants, red supergiants.