Finding Prime Factors:
factor(rationalNumber) returns the rational number factored into
primes.
If you are simply trying to decide if a number is prime, use isPrime( ). 
Example:
Find the prime factors of 72.
From a Calculator Page:
MENU  #2 Number  #2 Factor 

NOTE: According to the manual, the computing time for composite numbers grows exponentially with the number of digits in the secondlargest factor. Factoring a 30digit integer could take more than a day and a 100digit number could take more than a century.
Finding the Least Common Multiple (LCM):
lcm(Number1, Number2)
will return the least common multiple of the two numeric values.
Only accepts two values at a time. 
Example:
Find the LCM for 10, 15, and 45.
From a Calculator Page:
MENU  #2 Number
#3 Least Common Multiple
Since LCM can only accept two entries at a time, find the LCM of the first two values, and then find the LCM of your answer and the third value. 

Finding the Greatest Common Factor (GCF):
gcd(Number1, Number2)
will return the greatest common divisor of the two numeric values.
Only accepts two values at a time. 
NOTE: The calculator refers to the GCF as the GCD, greatest common divisor. 
Example:
Find the GCF (or GCD) for 12, 24, and 32.
From a Calculator Page:
MENU  #2 Number
#4 Greatest Common Divisor
Since GCD can only accept two entries at a time, find the GCD of the first two values, and then find the GCD of your answer and the third value. 

