That would be 1. The only factor of 1 is 1. All other whole numbers have at least two factors. Prime numbers have exactly two factors, while composite numbers have more than two factors.
1 is the number less than fifty with the fewest number of factors. All other numbers have at least two factors (1, and the integer itself).
There are 12 numbers less than 150 which have an odd number of factors: 1,4,9,16,25,36,49,64,81,100,121,144.
840
36
36
the number 90 has the most factors under 100
The three greatest whole numbers less than 200 that each have an odd number of factors are 144, 169 and 196.
360, 420 and 480 each have 24 factors.
The numbers 60, 72, 84, 90, and 96 each have 12 factors.
There are four odd numbers less that 100 that have 6 factor. This does not compare with even numbers that have 12 factors!
45, 63, 75 and 99 each have six factors.
60, 72, 84, 90 and 96 each have twelve factors.