What 5 numbers less than 100 have 12 factors?

Answer 1

These are the numbers and their factors.

60 (1,2,3,4,5,6,10,12,15,20,30,60)

72 (1,2,3,4,6,8,9,12,18,24,36,72)

84 (1,2,3,4,6,7,12,14,21,28,42,84)

90 (1,2,3,5,6,9,10,15,18,30,45,90)

96 (1,2,3,4,6,8,12,16,24,32,48,96)

Note : If you learn about number theory then the value of the exponents of the prime factors enables you to determine the number of factors.

For example : 60 = 22 x 3 x 5 = 22 x 31 x 51

Add 1 to the value of each exponent and obtain the product.

(2 + 1)(1 + 1)(1 + 1) = 3 x 2 x 2 = 12 ....which is the number of factors of 60.