"Google employs more than 130,000 contractors and temp workers, a shadow work force that outnumbers its 123,000 full-time" [1]

130K+123K = 253K (article from May, likely closer to 260K now)

One of the main points this group is making is that they want to equally represent fulltime employees and contractors.

"All Alphabet workers deserve a voice: full-time employees, temporary employees, contractors, and vendors. We care for and support each other by striving for open and continuous dialogue among union members." [2]

[1] https://www.nytimes.com/2020/05/29/technology/google-rescind... [2] https://alphabetworkersunion.org/principles/mission-statemen...