The base ten number system is very old and was almost certainly developed in a number of different places. The reason for this is that many people learn to count on their fingers, particularly in cultures that do not discourage the practice, and most people have ten fingers.
There is at least on place (in Spain) where most people have twelve fingers, and local people there often use a base twelve number system.
Early cultures had other systems, usually more complicated, such as the ancient Babylonian system of twenties and sixties, which historically gave us a circle of 360 degrees. The 360 degree circle is better suited to mathematics than a 100 degree circle, so it has historically been retained.
Some sociaties have chosen simpler systems, such as binary.
But the ten-based system seems to be cross cultural and most common world-wide. Its development is certainly prehistoric.
The Arabic numeral system, which is base ten, developed in the middle east and India.
The base of the Chinese number system is ten.
The number system commonly used by humans is base-ten.
The base is 10.
The decimal system is based on the number ten.
As far as I can see, 5649808 is already in the base ten number system.
In any system of counting, there are exactly the same number of digits as the base. They go from 0 to one less than the base.
Because each digit is ten times the one to the right of it.