It's about 4,000,000,000 times as long as a Strand of Spaghetti (thickness)
In other words, 6,400 kilometers is 3,800,000,000 times the length of a Strand of Spaghetti (thickness), and the length of a Strand of Spaghetti (thickness) is 0.000000000260 times that amount.(average; restaurant and supermarket applications) (based on FMA Omcan Italian Made TR50 Counter Top Pasta Machine Extruder 13317)
An average strand of restaurant-grade spaghetti measures 0.00000170 kilometers in thickness. In 2010, a California Buca di Beppo set a world record by preparing a 13,780-lb bowl of spaghetti, served in a swimming pool.
It's about 5,000,000,000 times as long as a Grain of Sand
In other words, 6,400 kilometers is 5,120,000,000 times the length of a Grain of Sand, and the length of a Grain of Sand is 0.0000000001950 times that amount.(medium grain)
Composed mainly of quartz, mica, feldspar, or magnetite, a grain of sand measures an average of 0.000001250 kilometers. In 2007, a team of seven in Myrtle Beach created the world's tallest sandcastle, which measured 0.0151 kilometers in height.
It's about 60,000,000,000 times as tall as a sheet of Paper
In other words, the height of a sheet of Paper is 0.0000000000200 times 6,400 kilometers.(for US Letter, a.k.a. ANSI A; 215.9mm by 279.4mm (8.5 in x 11 in); 20lb)
A single sheet of 20 lb, 8.5 inch x 11 inch paper is just 0.0000001000 kilometers thick. This style of paper weighs a mere 5 g per sheet.
It's about 65,000,000,000 times as long as a Strand of Hair
It's about 65,000,000,000 times as tall as a Human hair, Strand of
It's about 850,000,000,000 times as long as a Red Blood Cell
In other words, the length of a Red Blood Cell is 0.00000000000120 times 6,400 kilometers.(a.k.a. RBCs, a.k.a. haematids, a.k.a. erythrocyte, a.k.a. erythroid cells, a.k.a. red blood corpuscles)
An average Red Blood Cell measures 7.5 µm (micrometers) in diameter. An average human has 20 - 30 trillion red blood cells in their body and each cell completes a circulatory lap in about 20 seconds.
It's about 1,000,000,000,000 times as long as a Nucleus (Cellular)
In other words, 6,400 kilometers is 1,100,000,000,000 times the length of a Nucleus (Cellular), and the length of a Nucleus (Cellular) is 0.000000000000910 times that amount.(for animal cell)
The nucleus of an animal cell measures an average of 0.00000000600 kilometers. The nucleus is the largest organelle in these cells, accounting for about 10% of the cell's total volume.