Babylonian cuneiform numerals
The Babylonians, who were famous for their astronomical observations, as well as their calculations (aided by their invention of the abacus), used a sexagesimal (base-60) positional numeral system inherited from either the Sumerian or the Akkadian civilizations.
This was an extremely important development because non-place-value systems require unique symbols to represent each power of a base (ten, one hundred, one thousand, and so forth), which can make calculations more difficult.
They lacked a symbol to serve the function of radix point, so the place of the units had to be inferred from context: ๐๐๐น๐น๐น could have represented 23, 23ร60 (๐๐๐น๐น๐นโฃ), 23ร60ร60 (๐๐๐น๐น๐นโฃโฃ), or 23/60, etc.
The legacy of sexagesimal still survives to this day, in the form of degrees (360ยฐ in a circle or 60ยฐ in an angle of an equilateral triangle), arcminutes, and arcseconds in trigonometry and the measurement of time, although both of these systems are actually mixed radix.
[3] A common theory is that 60, a superior highly composite number (the previous and next in the series being 12 and 120), was chosen due to its prime factorization: 2ร2ร3ร5, which makes it divisible by 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60.
