One hundred and five, or 105, is a number that is known as a "highly composite number." This means that it has a large number of factors, with 1 and itself being the smallest and largest factors, respectively. In this article, we will explore some interesting facts and applications of the number 105.
The Factors of 105

As mentioned before, 105 has many factors. In fact, it has 8 factors in total, which are:
- 1
- 3
- 5
- 7
- 15
- 21
- 35
- 105
This makes 105 a highly composite number, as it has more factors than any other number up to 105.
The Mathematics of 105
105 is also an odd number, which means that it cannot be divided equally into two whole numbers. It is also a semiprime, which means that it is the product of two prime numbers. In this case, 105 equals 3 times 5 times 7, which are all prime numbers.
Moreover, 105 is the sum of the first 14 odd numbers, which are:
- 1
- 3
- 5
- 7
- 9
- 11
- 13
- 15
- 17
- 19
- 21
- 23
- 25
- 27
This property makes 105 a centered octagonal number, as it can be arranged in the shape of an octagon with 105 dots, with the first and last rows having 1 and 14 dots, respectively.
The Application of 105
105 has several practical applications in various fields. For example, it is a common weight for dumbbells used in fitness training. It is also used as a radio frequency for broadcasting in Japan, under the name "NHK Radio 1" or "NHK-FM."
Moreover, 105 is the maximum speed limit on certain highways in the state of California in the United States, as well as in several other countries. It is also the number of stories in the tallest building in Bangkok, Thailand, called the King Power Mahanakhon.
Conclusion
From its mathematical properties to its practical applications, 105 is certainly a fascinating number. Its large number of factors and oddness make it unique, while its use in different fields showcases its versatility and usefulness.
