What's the special significance of 12 1?

122: Road traffic accident alarm.

123 15: consumer complaint hotline.

Is the 90th complex number, and the positive factors are 1, 1 1, 12 1. The last one is 120, and the next one is 122. The 9th deficit1time, the sum of true factors is 12, and the deficit is 109. The last one is 1 19, and the next one is 122. The 40th semi-prime number. The last one is 1 19, and the next one is 122.

12 1 number generation:

The earliest tools used by human beings to count are fingers and toes, but they can only represent numbers within 20. When the number was large, primitive people mostly counted pebbles and beans. Gradually, people were not satisfied with counting by grains, so they invented the method of knotting to describe counting, and described counting on hides, bones, trees and stones.

In ancient China, counting was done with sticks made of wood, bamboo or bones, which was called counting chip. These counting methods and symbols gradually became the earliest digital symbols (numbers). Today, all countries in the world use Arabic numerals as standard numbers.