‘And the life of Sarah was one hundred and twenty seven years. These were the years of the life of Sarah.'
As mentioned of ages before, this age may not necessarily be intended literally (see on Genesis 5). It is one of those ending in seven as with Ishmael (Genesis 25:17) and Jacob (Genesis 47:28). Otherwise dates connected with Abraham and his descendants tend to end in nought or five. But it does indicate a good age.
Ishmael and Jacob were distinctive in dying outside the land of promise. It may be that Sarah, as a woman, is also not seen as directly connected with the promise. But in the end, while recognising that numbers are symbolic, we must admit that we do not know conclusively what their final significance was. After all Joseph died outside the land at one hundred and ten.