Divisibility of 7623? - Answers

A number is a multiple of 7623 if it's a multiple of 7, 9 and 121 at the same time 7623 = 3^2 x 7 x 11^2 = 9 x 7 x 121 A number is a multiple of 7 if the difference between twice the last digit and the rest of the number is a multiple of 7 A number is a multiple of 9 if the sum of the digits is a multiple of 9 A number is a multiple of 121 if the difference between 12 times the last digit and the rest of the number is a multiple of 121 For example 15246 is a multiple of 7 because 1524 - 6 x 2 = 1512 and 1512 is a multiple of 7. It's a multiple of 9 because 1 + 5 + 2 + 4 + 6 = 18 and 18 is a multiple of 9. It's a multiple of 121 because 1524 - 6 x 12 = 1452 and 1452 is a multiple of 121. Since it's a multiple of 7, 9 and 121 it means it's a multiple of 7623