A squat cement monument, topped with a chocolate-brown arm gripping the replica of an Olympic-style flaming torch, dominates the main roadway leading into this regional capital of Shaba Province. Close by, a large faded green billboard spells out in yellow letters: "Mobutu Sese Seko -- Our Only Hope."

Variously known in the government-run media as "The Guide," "Our Savior" and "The Prophet," the charismatic and imperious 49-year-old Mobutu has maintained power through ruthless suppression and the shrewd use of what one Western diplomat called "illusions, mirrors and gimmickry."

An Army general in the turbulent five years following independence in 1960, Joseph Mobutu, as he was then known, came to power in a U.S.-backed coup in November 1965, when Zaire was still called the Congo.

Although he originally pledged to run the country only five years, Mobutu Sese Seko Kuru Ngebendu Wa Za Banga, as he is now known, has for the past 14 years presided over this potentially rich Central African country's brief ascendency toward prosperity and its subsequent rapid degeneration into threadbare poverty.

Mobutu's enormous staying power is attributed by political observers to his skillful political manipulations that fluctuate between occasional cosmetic reforms and steady reliance on raw power.

He formed Zaire's only legal political party, the Popular Movement for the Revolution, appointed himself head of the government's legislative, judicial and executive branches, and created a network of party informers and an efficient secret police organization, known as the National Documentation Center.

Mobutu also molded all labor unions into one, which was incorporated in his party. University students, large numbers of whom were killed when they demonstrated against Mobutu at the outset of his rule, were eventually brought into the party framework.

Although he permitted nationwide elections in 1977 for a legislative council, there was never any doubt where the ultimate decision-making authority lies.

Yet under his rule, Zaire's debt to Western governments and banks has grown to $5 billion while domestic corruption has reached such proportions that an estimated 40 percent of all government funds winds up in the pockets of government officials.

In the process, Mobutu has advanced from a salaried Army officer to become one of the world's richest men.

Mobutu started out as a popular national figure whose government brought stability following Zaire's political turmoil of the early 1960s. His emphasis on cultural African nationalism, or Zairism "authenticity," also found popular acceptance.

First, he changed the name of the country from the Democratic Republic of the Congo to Zaire, then created Zaire's distinctive attire, the so-called abacost. He justified his one-man rule as consistent with pre-colonial Zairian traditions.

In the early 1970s, while still enjoying popularity at home, Mobutu also took an active role in Third World affairs, criticizing South Africa and leading the Africa-wide break of diplomatic relations with Israel following the 1973 Middle East war.

In that period he startled Washington by his public charges that the CIA had tried to assassinate him and topple his government. Diplomats saw this as a ploy to gain credibility in the Third World. "You aren't somebody in the Third World until the CIA tried to assassinate you," one European diplomat said.

By 1976 Zaire was in dire economic straits. As a result of mismanagement, corruption and a drastic drop in the world price of copper, Zaire's main export and revenue source, Mobutu became increasingly dependent on Western banks and governments.

The civil war in Angola closed the Benguela railroad, leaving Mobutu dependent on South Africa's railways to the ports of East London and Durban. In turn, he muted all criticism of South Africa's racial policies. d

Mobutu also has reached a compromise with the Roman Catholic Church after an open conflict over a decree prohibiting Western names. Pope John Paul Ii is scheduled to visit Zaire next year, a tribute to the changed relationship.

While growing increasingly resentful of the oil-rich Arab nations, whose support he had wooed, Mobutu has mended his relations with the United States. He visited President Carter in Washington last September.

His popularity at home declined sharply after Angola-based rebels invaded Shaba in 1978 and economic difficulties that followed the drop in copper prices. But he continued to run Zaire with an iron hand, eliminating all dissent. An unknown number of political prisoners are tortured.

In an effort to preclude any coups, Mobutu has sought to divide potential opponents by setting ethnic groups against each other. "He took his lesson from the Belgians," Zaire's former colonial rulers, one Zairian said.

Mobutu's closest advisers are all from his Equateur region while key military men come either from the president's province or from Upper Zaire in the northeast. But the generals report directly to him and informants say that his soldiers are "recruited from all trides except those" in the rebellious Shaba region.

"This is how he maintains Shaba's security and his own," one source said.

By excluding Shabans from the government, according to the sources, Mobutu has made other ethnic groups wary of the southern tribes.

"It is like juggling," one Zairian described Mobutu's policies. "It keeps everybody off balance."

Mobutu has done the same with Western countries that support his government. "We're his major supporters," a European diplomat said.

"But he does the same thing to us he does to everyone, plays us off, one against the other."