A number is said to be regular if its prime factor decomposition has only powers of 2, 3, and 5.

Example:

60 is a regular number because 60 = 2².3.5.

A number is said to be regular if its prime factor decomposition has only powers of 2, 3, and 5.

Example:

60 is a regular number because 60 = 2².3.5.