Wayne Scott was jailed for 19 years in 2013 for a series of rapes and other sex offences over a 10-year period.
A report into his offending found some of his crimes could have been avoided if colleagues at Cleveland Police had acted on his "red flag" behaviour.
The force apologised to victims for its "unacceptable" failings.
Scott, from Stockton, was convicted of raping two women at Newcastle Crown Court. He also pleaded guilty to a sex offence involving a child.
The report, conducted by the Cleveland force under the supervision of the Independent Police Complaints Commission (IPCC), said Scott, who joined the force in 2002, repeatedly bragged about sexual activity and attempted to humiliate female colleagues while working in Stockton and Hartlepool.
It highlighted how he preyed on vulnerable female offenders and demanded sex from them on several occasions.
Scott, 38, boasted to colleagues about a phone he kept in a locker at work, which he used to contact "girlfriends", the report discovered.
It also found he played a "rape game" where he would ask women, some of them fellow officers, if they were "interested in him".
Deputy chief constable Ian Spittal said: "I want to sincerely apologise to everyone who has been affected by the actions of Wayne Scott whilst he was a serving officer with Cleveland Police.
"It's clear from the findings that officers and staff felt unable or unwilling to challenge his sexual remarks and degrading behaviour at work.
"Where incidents were reported, we accept that red flags were missed and the organisation dealt with cases in isolation, rather than joining the dots.
"This is unacceptable and we have reviewed and changed many of our practices."
The report made 15 recommendations to the Cleveland force, including better monitoring of officers who have regular contact with vulnerable women, particularly sex workers and victims of domestic violence.
Cleveland's police and crime commissioner Barry Coppinger said: "This report lays bare the shocking behaviour of Wayne Scott and details what was known about him during his time as a serving officer. It's vital that Cleveland Police implements the recommendations from the report as swiftly as possible.
"It is completely unacceptable that his disgusting behaviour went unchallenged for so long."
The "degrading behaviour" of a police officer jailed for multiple rapes was allowed to "flourish" unchallenged, a report has found.