 Integers larger than the square root do not need to be checked because, whenever formula_205, one of the two factors formula_34 and formula_39 is less than or equal to the square root of formula_1.Another optimization is to check only primes as factors in this range.For instance, to check whether 37 is prime, this method divides it by the primes in the range from 2 to , which are 2, 3, and 5.