How many Tirthankar are present today ?
According to Jainism, there are no living Tirthankaras present in the current era (Avasarpini) on our Bharata Kshetra (the present world/continent). The 24th and last Tirthankara of the current cycle was Lord Mahavira, who attained nirvana (liberation) around 527 BCE. Since then, no new Tirthankara has appeared in this time cycle.
However, Jain scriptures mention that in the next time cycle (Utsarpini), new Tirthankaras will appear. Also, according to Jain cosmology, Tirthankaras may exist in other realms or continents, but not in our current Bharat Kshetra at this time.