[Franciscouzo]

If you read the article, it's actually:

(2^77,232,917)-1

[chrismorgan]

Very well then; let us rather write them with proper superscripts (and I’ll use THIN SPACE as a thousands and prettiness separator too because I can):

2 ⁷⁷ ²³² ⁹¹⁷ − 1

not

2 ⁷⁷ ²³² ⁹¹⁷ ⁻ ¹

There, no more ambiguity.

(Now I’m waiting for someone to jump on me to correct anything subtle.)

[Ah, I see, the parentheses were indeed a red herring. Ah well; let the superscripts remain.]

[TheRealPomax]

Not sure if this was a serious comment, but if it was: due to operator precedence in mathematics, the expressions (2^77,232,917)-1, 2^(77,232,917)-1, and 2^77,232,917-1 are identically evaluated, with the parentheses only used to aid the human eye. This in contrast to 2^(77,232,917-1), which is 2^77,232,916 and is a very different number indeed.

[kodablah]

The parens are a red herring. GP is commenting on the previous poster using 277 instead of 77 (i.e. typo).