Which of the following numbers is divisible by 4?

1. 308594

2. 506784

3. 732106

4. 9301538

A number is divisible by 4 if the number formed by its last two digits is divisible by 4.

1. 308594: last two digits = 94, not divisible by 4.

2. 506784: last two digits = 84, and 84 ÷ 4 = 21, divisible by 4. ✓

3. 732106: last two digits = 06 = 6, not divisible by 4.

4. 9301538: last two digits = 38, not divisible by 4.

Hence, option 2 is the correct option.