The skyscraper adjacent to Carnegie Hall is not paying the piper.

Comptroller John Liu said yesterday his auditors have determined that Carnegie Hall Tower, a 60-story building, owes the city as much as $2.1 million in past-due rental payments and penalties.

The city collects a percentage of rent that the tower pays Carnegie Hall under a subsidy agreement last updated in 1993.

Liu said the tower deducted $8.7 million in expenses without approval and failed to report another $224,000 in income.

City officials blamed a “technical oversight.’’

dseifman@nypost.com