👉 In number theory, divisibility refers to whether a given number can be divided by another number without leaving a remainder. For example, 15 is divisible by 3 because you can divide it into three parts and have one part left over (i.e., 15 ÷ 3 = 5). In general, if we have two numbers that are relatively prime (meaning their greatest common divisor is 1), then they are said to be "divisible" by each other.
