The sum of the digits $a_0 + a_1 + \dots + a_k$ is divisible by 8.

The alternating sum of the digits $a_0 - a_1 + a_2 - \dots + (-1)^k a_k$ is divisible by 8.

The last digit $a_0$ is even.

The sum of the digits $a_0 + a_1 + \dots + a_k$ is divisible by 6.