@Shaik Masthan Sir.
According to me we can also construct a synchronous binary mod N counter. and it will have ceil(logn ) counters.
Counters can have any sequence of states.
And here binary mod N counters means that it follows binary sequence like (0-1-2-3-4..... upto 2^n-1 )and then this cycle repeats.
According to Morris Mano "A counter that follows binary sequence is called binary counters"
Am I correct?