Probably something below 20 Hz. They are done with rotating motors with unbalanced shafts. Here is a page that shows lots of products.
http://www.precisionmicrodrives.com/vibration_motors.php?_kk=cell%20phone%20vibrator%20motor&_kt=c8a02ca2-cd5f-4ac0-918f-9e11e3edc018&gclid=CNv2td_zuJ4CFQ8eDQodfUIwmA
My guess is the shaft spins on the order of 5 or 20 rev/sec - giving a fundamental frequency of 5 to 20 Hz. Maybe 10 Hz...
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Depends on the cell phone.
kilograms
go to recent call then go to cal duration on your cell phone if that doesnt work then you can probley call your cell phone company
say"excuse me by cell phone just died, can I use your phone for just a sec?" then call your cell phone this way you both have each other's numbers.
Your cell phone, your TV, your "radar range".