Explanation

A number is divisible by 11 if the difference between the sum of its digits in odd positions and the sum of its digits in even positions is a multiple of 11 (including 0).

For 7879553:

• Sum of odd-positioned digits = 7 + 7 + 5 + 3 = 22
• Sum of even-positioned digits = 8 + 9 + 5 = 22
• Difference = 22 - 22 = 0 (which is a multiple of 11)

Thus, 7879553 is divisible by 11.