The representation of numbers has been evolving since antiquity and will surely continue to evolve in the future. If we read the history of mathematics, different civilizations had different representations of numbers.
One of the old numerals that we still use is the Roman numerals. The advent of computers and the development of number theory developed finite number systems such as the binary, octal and hexadecimal system as well as the their representations. The first two use digits of the decimal number system while hexadecimal uses the letters of the alphabet to represent digits greater than 9.
The most recent number representation was invented by Jaime Redin. Redin invented another system of writing numbers particularly for entering in calculators and other electronic devices. Verbal numbers as he calls it, aims to make writing more intuitive than the positional system we use. Verbal numbers use the letters T for thousand, M for millions, and B for billions. Hence, the number 2, 072,030, 185 can be written as 2M72T30 and the number 2,000,001 is represented by 2M1. This means that the calculator that will use Verbal numbers will have the letters T, M, and B included, and probably other letters to represent larger numbers. In addition, machines that will be using Verbal numbers will have to develop a new algorithm in computations.
The details of Redin’s Verbal numbers can be read here.