It's about 0.0000000005 times as heavy as a Tree (Sierra Redwood).
In other words, 645.5 miligrams is 0.0000000005 times the weight of a Tree (Sierra Redwood), and the weight of a Tree (Sierra Redwood) is 2,000,000,000 times that amount.(a.k.a. Giant Sequoia, a.k.a. Sierran redwood, a.k.a. Wellingtonia, a.k.a. "Big Tree", Sequoiadendron giganteum)
The weight of wood in a Giant Sequoia is 1,300,000,000,000 miligrams. General Sherman, a specimen in Sequoia National Park in Visalia, California, is the largest tree in the world by volume, with an estimated weight of about 1,900,000,000,000 miligrams.
It's about 0.00000000007 times as heavy as The Eiffel Tower.
In other words, 645.5 miligrams is 0.0000000000639 times the weight of The Eiffel Tower, and the weight of The Eiffel Tower is 15,600,000,000 times that amount.(a.k.a. La Tour Eiffel) (Paris, France) (total weight)
The Eiffel Tower weighs approximately 10,100,000,000,000 miligrams. Architected to be quickly assembled, the Tower contains only 7.5 cu. m (260 cu. ft) of solid material.
It's about 0.00000000005 times as heavy as The Brooklyn Bridge.
In other words, 645.5 miligrams is 0.00000000004846 times the weight of The Brooklyn Bridge, and the weight of The Brooklyn Bridge is 20,640,000,000 times that amount.(a.k.a. New York and Brooklyn Bridge) (Manhattan and Brooklyn, New York City, New York) (total weight)
The total weight of the Brooklyn Bridge is approximately 13,320,000,000,000 miligrams. In a promotional event to prove the bridge's stability shortly after it opened, entertainer P. T. Barnum led a parade of 21 elephants across it in May of 1884.
It's about 0.00000000003 times as heavy as The Statue of Liberty.
In other words, 645.5 miligrams is 0.000000000026 times the weight of The Statue of Liberty, and the weight of The Statue of Liberty is 38,000,000,000 times that amount.(a.k.a. Liberty Enlightening the World, a.k.a. La Liberté éclairant le monde) (total weight, including foundation)
The total weight of the Statue of Liberty is roughly 24,000,000,000,000 miligrams. The statue was designed using an optical trick known as "forced perspective" to make the statue appear proportionally correct when viewed from its base and is, in actuality, disproportionately large at the top.
It's about 0.000000000006 times as heavy as The CN Tower.
In other words, 645.5 miligrams is 0.0000000000054745 times the weight of The CN Tower, and the weight of The CN Tower is 182,670,000,000 times that amount.(a.k.a. La Tour CN, a.k.a. Canadian National Tower, a.k.a. Canada's National Tower) (Toronto, Canada)
The CN Tower weighs approximately 117,910,000,000,000.0 miligrams. The Tower is home to the world's highest glass floor — a viewing area that allows visitors to look straight down 342 m (1,120 ft) to the ground below.
It's about 0.000000000003 times as heavy as The Sears Tower.
In other words, 645.5 miligrams is 0.000000000003199 times the weight of The Sears Tower, and the weight of The Sears Tower is 312,600,000,000 times that amount.(officially "Willis Tower" as of 2009) (Chicago, Illinois)
The Willis Tower weighs approximately 201,800,000,000,000.0 miligrams. The outer wall surface of the Tower is covered with black anodized aluminum panels which would total 110,000 sq. m (28 acres) if laid out together.
It's about 0.000000000002 times as heavy as The Empire State Building.
In other words, 645.5 miligrams is 0.00000000000195 times the weight of The Empire State Building, and the weight of The Empire State Building is 513,000,000,000 times that amount.(New York City, New York)
The Empire State Building weighs approximately 331,000,000,000,000.0 miligrams. About 4% of the building's weight is its 6,000 cu. m (200,000 cu. ft) of limestone façade.