97=97
997=997
9997=13×769
99997=19的2次方×277
999997=757×1321
9999997=7×1428571
99999997=1297×77101
999999997=71×2251×6257
9999999997=13×769230769
99999999997=17×5882352941
999999999997=5507×181587071
9999999999997=7的2次方×56527×3610339
99999999999997=839×119189511323
999999999999997=599×2131×3733×209861
9999999999999997=13×433×39323×45177491