An odd number is an integer that is not divisible by 2. In other words, it has a remainder of 1 when divided by 2. For example, 3, 5, and 7 are all odd numbers because they leave a remainder of 1 when divided by 2.

207 is an odd number because it leaves a remainder of 1 when divided by 2. You can confirm this by dividing 207 by 2: 207 / 2 = 103 with a remainder of 1. Since 207 has a remainder of 1 when divided by 2, it is classified as an odd number.