I had the same problem with the odometer in a 1993 pickup (same one as a 4Runner) with electronic speedo. The numbers stopped turning between 199,999km and 200,000 km.
The trip odometer was also hard to reset on mine. I removed the cluster and sprayed some WD 40 in it between the numbers. The trip odometer was much easier to reset and the odometer was working again after that. The only minor problem I noticed after I sprayed WD 40 was a greasy film appearing on the speedo faceplate around the odometer numbers. I didn't remove the cluster just to clean it.
Maybe there's something better to lubricate the sticky numbers but that's all I had on hand when I did the job and it worked!