How many kids did st Sarah and Abraham have?

Sarah and Abraham had one son, Isaac, who was born when Abraham was 100 years old and Sarah was 90. Additionally, after Sarah's death, Abraham married Keturah and had six more children: Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah. However, Isaac is the child most prominently featured in biblical narratives regarding Abraham and Sarah.