There are 5 significant figures in the number 84062.
There are 5 digits at all, and none of them are leading zeros (they are always insignificant). Also there are no trailing zeros (they are sometimes considered insignificant).
And because we know nothing about the precision of the original data, if this number is obtained from some calculations, we have to assume all digits significant.
Zero inside the number is significant, too, because it gives important information: there is no hundreds in this number (but thousands are there and tens too).