▁well . ▁For ▁many ▁disk ▁drives , ▁at ▁least ▁one ▁of ▁the ▁sector ▁size , ▁number ▁of ▁se ctors ▁per ▁track , ▁and ▁number ▁of ▁tracks ▁per ▁surface ▁is ▁a ▁power ▁of ▁two . ▁The ▁logical ▁block ▁size ▁is ▁almost ▁always ▁a ▁power ▁of ▁two . ▁ ▁Num bers ▁that ▁are ▁not ▁powers ▁of ▁two ▁occur ▁in ▁a ▁number ▁of ▁situations , ▁such ▁as ▁video ▁resolution s , ▁but ▁they ▁are ▁often ▁the ▁sum ▁or ▁product ▁of ▁only ▁two ▁or ▁three ▁powers ▁of ▁two , ▁or ▁powers ▁of ▁two ▁minus ▁one . ▁For ▁example , ▁, ▁and ▁. ▁Put ▁another ▁way , ▁they ▁have ▁fairly ▁regular ▁bit ▁patterns . ▁ ▁M ers enne ▁and ▁F erm at ▁pr imes ▁ ▁A ▁prime ▁number ▁that ▁is ▁one ▁less ▁than ▁a ▁power ▁of ▁two ▁is ▁called ▁a ▁M ers enne ▁prime . ▁For ▁example , ▁the ▁prime ▁number ▁ 3 1 ▁is ▁a ▁M ers enne ▁prime ▁because ▁it ▁is ▁ 1 ▁less ▁than ▁ 3 2 ▁( 2 5 ). ▁Similarly , ▁a ▁prime ▁number ▁( like ▁ 2 5 7 ) ▁that ▁is ▁one ▁more ▁than ▁a ▁positive ▁power ▁of ▁two ▁is ▁called ▁a ▁F erm at ▁prime — the ▁exponent ▁ ▁itself ▁is ▁a ▁power ▁of ▁two . ▁ ▁A ▁fraction ▁that ▁has ▁a ▁power ▁of ▁two ▁as ▁its ▁denomin ator ▁is ▁called ▁a ▁dy adic ▁rational . ▁The ▁numbers ▁that ▁can ▁be ▁represented ▁as ▁sums ▁of ▁consecutive ▁positive ▁integers ▁are ▁called ▁pol ite ▁numbers ; ▁they ▁are ▁exactly ▁the ▁numbers ▁that