As a result of a typographical error, an item in last week's Think Tank gave the wrong figure for the number of Iranian students in this country. The number is 51,970.

More than 286,000 foreign students -- the most ever -- were enrolled in United States colleges and universities last year, with most pursuing degrees in engineering, business and management, according to a survey by the Institute of International Education.

The survey, which is based on responses from 2,950 institutions, revealed that the students came from 181 countries, one-third of them from member nations of the Organization of Petroleum Exporting Countries.

Nearly 60 percent were from Asian countries, while 15 percent were from Latin America, 13 percent from Africa and 8 percent from Europe. The remainder were from North America and Oceania.

Topping the list of nations sending students was Iran, with 5,870 formally enrolled in academic programs; Taiwan was second with 17,530. Other nations supplying large numbers were, in order, Nigeria, Canada, Japan, Venezuela, Saudi Arabia, Hong Kong, India and Thailand.

"The presence of four OPEC nations among the top 10 countries of origin indicates the high priority the oil-rich nations place on education," the report said.

"As recently as 1968-69, OPEC states accounted for only 9 percent of the total. This year, they accounted for 101,160 students, over 35 percent of all foreign students," it said.

Only 18 percent of the students reported that their prime source of funds came from this country; 82 percent said they got their primary support from personal or family funds, their home government or other home country sources.

The largest number of students chose engineering as their field of study, followed by business and management. These were followed in popularity by the social and natural sciences, mathematics and computer sciences, the arts, education, the humanities, health and agriculture.

California had the most foreign students, with 47,000 followed by Texas, New York, Massachusetts and Illinois, which reported 12,218. The University of Southern California had the largest international student population, 3,305.