It’s correct to use “others” as the plural and “other’s” to talk about the singular possessive. You can use “others’” as a plural possessive, but it’s much more likely that you’ll require a secondary noun for this to make sense (i.e. “other people’s”).

Another’s is the correct possessive singular form of the word another. Anothers is incorrect because there is no plural form of another. Anothers’ is also not possible because there is no plural possessive of another. Another means one more and therefore there is no plural. If you need to use more than one more, then you can use others.

A simple rule to help you remember the difference is: another + singular noun other + plural noun others (a pronoun to replace other + plural noun) I need another cup. (cup is singular so we use another) I need other cups. (cups is plural so we use other) I need others. (refers to other cups)

The answer depends on whether “others” refers to the singular or plural possessive. If you are using each other (singular), then it is “each other’s.” If you are using the plural, then the apostrophe goes after the “s.”