American Telephone & Telegraph Co., likely to lose its title next year as the world's largest corporation, yesterday reported record 1981 revenues of $58.2 billion and profits of $6.89 billion.

Profits of the Bell System, the nation's most widely held corporation, rose by 4.7 percent to $8.55 a share on 788 million average shares outstanding, compared with 1980 earnings of $6.06 billion ($8.17) on 724 million shares, with revenues of $50.9 billion.

Charles L. Brown, chairman of the telecommunications industry leader that signed an agreement almost a month ago with the Justice Department calling for the divestiture of 22 of its 24 local operating subsidiaries, said yesterday the landmark agreement "should not overshadow the very significant accomplishments of the Bell System" last year.

That agreement is unlikely to be implemented until late next year, 18 months after a federal judge is expected to approve the plan. In exchange, the Justice Department has agreed to drop a seven-year-old antitrust suit against the company and has agreed to modify a 1956 agreement between the two parties.

Meanwhile, AT&T reported that its overall business volume last year--revenue growth adjusted to remove rate changes--rose by 8.6 percent last year. Local revenues last year rose by 13.8 percent over 1980 to $25.5 billion, while long distance revenues rose by 15.7 percent to $30.2 billion.

The company's rate of return (profits related to total investment) for the year rose to 10.3 percent, compared with 9.9 percent in 1980, while return on the company's 1981 common equity of $52 billion rose from 12.68 percent to 12.9 percent. AT&T's expenses and taxes rose by 14.4 percent to $47.9 billion, though the company's work force dropped by 0.4 percent to 1.04 million employes.

Brown said demand for some AT&T services fell short of company projections, "reflecting in part an economy that started the year strong but closed in recession." Federal and state regulators granted the company 1981 rate increases totaling about $1 billion annually from interstate long distance services and hikes of about $3.2 billion a year in local increases.

Other corporate earnings yesterday, compiled from news services, included:

Tenneco Inc., the nation's 11th-largest oil company, said yesterday that profits increased 12 percent in 1981 over the previous year, boosted by a sharp rise in earnings during the last three months.

J. L. Ketelsen, Tenneco chairman and chief executive, said the company had net income last year of $813 million ($6.01), compared with $726 million ($5.95) in 1980. Fourth-quarter earnings rose 30 percent from $200 million ($1.56) to $260 million ($1.91).

Sales rose to $15.46 billion in 1981 from $13.23 billion in 1980 and to $4.29 billion in the fourth quarter from $3.64 billion a year earlier.

Ketelsen said per-share earnings were diluted by the issuance of 10.1 million shares of stock when Tenneco purchased Houston Oil and Minerals Corp. That acquisition increased Tenneco's domestic oil and gas exploration acreage by 1.4 million net undeveloped acres, bringing the company's total to 7.5 million acres at the end of the year, Ketelsen said.

He said Tenneco businesses other than energy that contributed to the gains were construction and farm equipment, shipbuilding, packaging, insurance and automotive. Integrated oil operations were the big profit contributor in the energy division.

Sales of Tenneco's Newport News Shipbuilding and Dry Dock Co. surpassed $1 billion in 1981 for the first time at $1.1 billion, up from $891 million in 1980, President and Chief Executive Edward J. Campbell said.

Operating income rose for the third straight year, to $82 million from $55 million in 1980 and $33 million in 1979.

Return on assets also rose, to 27 percent last year from 18 percent in 1980, Campbell said.

He said 1981 "was obviously a very good year for our company, and 1982 should also be."

The shipyard, Virginia's largest private employer with a work force of about 25,000, entered 1982 with a $3.8 billion backlog of work, compared with $3.1 billion in 1980, Campbell said.

Most of this backlog represents Navy work. The yard is building two aircraft carriers and 10 fast-attack submarines for the Navy and a chemical carrier for Union Carbide Corp. Newport News Ship also has a large backlog of ship repair work.

"Employment is down only slightly from previous levels due to normal attrition, although minor slack periods may develop from time to time as a result of accelerated commercial ship schedules last year," Campbell said.

Some of the employes who worked on these projects are being shifted to military construction jobs to even out work assignments. "We plan to continue our efforts to maintain a relatively stable work force," Campbell said.

Knight-Ridder Newspapers Inc. earned $100.35 million ($3.09 a share) in 1981, up from $92.86 million ($2.87) in 1980 on a rise in sales to $1.237 billion from $1.098 billion.

Fourth-quarter profits inched up to $29.31 million (90 cents) on revenues of $331.6 million from $28.95 million (also 90 cents) on revenues of $303.01 million.