Sen. John Glenn (D-Ohio) earned at least $1.6 million in the past 16 months, far more than did his rivals for the Democratic presidential nomination, while former vice president Walter F. Mondale led the group in speaking fees from a variety of special-interest groups, according to financial disclosure statements released yesterday.

Glenn reported personal family income between $1.6 million and $2.1 million from Jan. 1, 1982, through April 15 of this year. It was mostly from holdings in two Holiday Inns near Walt Disney World in Florida, a broad range of corporate stocks and partnerships in real estate, timber and oil and gas.

His assets in property and stock, which under the disclosure rules also are listed in general ranges, were valued between $3.2 million and $7.4 million.

Mondale's family income during the same period was between $709,767 and $726,067, and his assets were valued from $138,000 to $375,000. His earnings included director's fees and a $150,000-a-year salary from the Winston and Strawn law firm, as well as $174,481 in speaking fees.

The roster of groups that Mondale has addressed reads like a campaign wish list for any Democratic fund-raiser. He received $21,000 for three speeches to the United Jewish Appeal, $10,500 from State of Israel Bonds, $7,000 from Yeshiva University, $7,000 from Blue Cross-Blue Shield, $2,000 from General Electric Corp. and $1,500 from the National Education Associaton.

The heftiest fees came from Borsen Corp., a European financial services group, which paid Mondale $14,000 for each of five speeches to businessmen in Amsterdam, Copenhagen and Helsinki.

"These groups know Walter Mondale, and they run the gamut of concerns," said Maxine Isaacs, Mondale's press secretary, adding that all the speeches were arranged by the Harry Walker Agency. "He wasn't seeking to address these groups. They are asking for him. He is not a captive of any special-interest group."

Among the other candidates, Sen. Ernest F. Hollings (D-S.C.) reported $91,870 in speaking fees during 1982 for addressing such groups as the Chemical Manufacturers Association and the Mortgage Bankers Association. Sen. Alan Cranston (D-Calif.) received $58,750 in honoraria, and Sen. Gary Hart (D-Colo.) $43,172 during the 16-month period.

Hart, like Mondale, has made an issue of rejecting contributions from political action committees. Spokesman Kathy Bushkin said that Hart wants to campaign "unencumbered by special interests," but that "there's a big difference between financing your campaign and accepting speaking fees."

A spokesman for Cranston said the honoraria have not influenced Cranston's voting record. But Glenn's campaign manager, Bill White, said Glenn does not accept speaking fees because "it's something he just doesn't feel comfortable doing."

Glenn earned $1.16 million from three corporations that own and manage the Holiday Inns, in which he has a 30 percent interest. One of Glenn's partners is a Florida businessman who helped Glenn and the other six original astronauts buy property in the early 1960s, campaign manager White said.

A Boston financial firm manages Glenn's portfolio of state and local bonds and stocks in such firms as American Express Co., IBM Corp., Owens Corning Corp., Patriot Oil and Gas, Long Pond Timber and Philip Morris Inc. White said Glenn's investment income shows "that he's a good businessman. He's made some good investments, and he's had some good opportunities."

Mondale, in addition to a $30,000-a-year federal pension, earned $95,109 as a director of Control Data Corp., $50,190 as a director of Columbia Pictures Industries and $50,000 as a consultant to Family Focus, a children's services group. He has since resigned from these groups.

Former Florida governor Reubin Askew reported earnings of $308,816 to $313,016, most of it from his salary as a senior partner in Miami's largest law firm.

Hart reported income of $171,424 to $175,024, including $16,750 in advances for two books. Cranston reported income of $184,347 to $307,447, while Hollings, who listed only 1982 figures, reported earnings of $339,062 to $511,862.

The size of the ranges varies because whereas those whose income is mainly from salary reported those figures exactly, those whose income is primarily from investments reported them within relatively broad ranges.