The greatest prime factor of the number of minutes in a week is...
12 and 21 aren't primes
Number of minutes in a week =
60 x 24 x 7 =
( 5 * 3 * 2^2) * ( 2^3 * 3) * (7) = 2^5 * 3^2 * 5 * 7
Greatest prime factor = 7
