“Other’s” is the correct possessive form of “other,” and we use it when we want to talk about “other” in the singular possessive form being in ownership of an object in the sentence.

Think about it like you are referring to “each other” (singular). In that case the word “other’s” is correct. It is like you are saying “each other’s.” With the plural form being others’.

Other’s is the correct possessive singular form of the word other. Others is the plural form of the word other. Others’ is the possessive plural of others.