Smallest number of five digits is 10000. Required number must be divisible by L.C.M. of 16,24,36,54 i.e 432, On dividing 10000 by 432,we get 64 as remainder. Required number = 10000 +( 432 – 64 ) = 10368.
Perfect Square : A number when written as product of prime factors , if each prime factor has even number as its power , then the number is perfect square. Writing the given number as product of prime factors 6 = 2 x 3 12 = 2³ x 3 18 = 2 x 3² 24= 2³ x 3 LCM = 2³ x 3² = 72 But 72 is not the perfect square. But multiples of 72 are also exactly divisible by given numbers. 72 x 2 =144 is the perfect square.