The number 19 stands for long-term significance. In addition, 19 has a magical attribute. Expand all the fractions from119 to 18/ 19 into decimals, and get a square of18. The special feature of this phalanx of numbers is that it is a Rubik's cube-the sum of the numbers on each row, column and diagonal is 8 1 (note: it is not a Rubik's cube in the strict sense, because there are the same numbers).

19 (XIX) is a natural number between 18 and 20. Belonging to odd numbers and prime numbers. This is an Arabic numeral. Is a positive integer. In number theory, 19 is a higner number.

The properties of 19 in mathematics;

1, the 20th natural number.

2. The19th positive integer.

3. The number 13 without square divisor. The last one is 17, and the next one is 2 1.

4. Decimal digit 13. The last one is 17, and the next one is 2 1.

5. Number of the fourth central triangle.

6. Hexagonal number of the third center.

7. The third octahedron number.

8, the eighth prime number. The last one is 17, and the next one is 23.

Refer to the above? Baidu Encyclopedia-19