Want to know which insect it is? I often found it in washroom. Is it dangerous and how to control it
That is a house centipede, Scutigera coleoptrata https://en.wikipedia.org/wiki/Scutigera_coleoptrata
They are harmless, unless you are a cockroach or termite. People find them unpleasant and creepy, because they run fast, but they are predators that prey on pests in your home. 
https://www.familyhandyman.com/pest-control/heres-why-you-should-never-kill-a-house-centipede/