Whats the smallest number ("the magic number") that can satisfy these conditions?

- its positive

- it is not divisible by any number below 20 (excluding 1)

- the average of the digits is an even number between 3 and 9

53 is the magic number
1. it is positive
2. It is not divisible by any number lower than 20:
    53/2=26.5
    53/3=17.67
    53/4=13.25
    53/5=10.6
    53/6=8.833
    53/7=7.571
    53/8=6.625
    53/9=5.89
    53/10=5.30
    53/11=4.818
    53/12=4.42
    53/13=4.08
    53/14=3.786
    53/15=3.533
    53/16=3.3125
    53/17=3.12
    53/18=2.944
    53/19=2.789
3. the average of its digits is 4 ((5+3)/2=4)

Posted by logischer Verstand on 2004-03-21 17:49:18