Calculate the total surface area and capacity of a regular octagonal based prism with side length 10 cm and height 50 cm.

The area of a regular octagon with side length $s$ is given by the formula $A_{base} = 2(1+\sqrt{2})s^2$.

$$A_{base} = 2(1+\sqrt{2})(10 \text{ cm})^2$$ $$A_{base} = 2(1+1.41421356)(100 \text{ cm}^2)$$ $$A_{base} = 2(2.41421356)(100 \text{ cm}^2)$$ $$A_{base} = 482.842712 \text{ cm}^2$$

The perimeter of a regular octagon with side length $s$ is $P = 8s$.

$$P = 8 \times 10 \text{ cm}$$ $$P = 80 \text{ cm}$$

The lateral surface area is $A_{lateral} = P \times H$.

$$A_{lateral} = 80 \text{ cm} \times 50 \text{ cm}$$ $$A_{lateral} = 4000 \text{ cm}^2$$

The total surface area is $A_{total} = 2 \times A_{base} + A_{lateral}$.

$$A_{total} = 2 \times 482.842712 \text{ cm}^2 + 4000 \text{ cm}^2$$ $$A_{total} = 965.685424 \text{ cm}^2 + 4000 \text{ cm}^2$$ $$A_{total} = 4965.685424 \text{ cm}^2$$

Rounding to two decimal places:

$$\boxed{4965.69 \text{ cm}^2}$$

The volume of a prism is $V = A_{base} \times H$.

$$V = 482.842712 \text{ cm}^2 \times 50 \text{ cm}$$ $$V = 24142.1356 \text{ cm}^3$$

Since $1 \text{ litre} = 1000 \text{ cm}^3$:

$$V_{litres} = \frac{24142.1356 \text{ cm}^3}{1000 \text{ cm}^3/\text{litre}}$$ $$V_{litres} = 24.1421356 \text{ litres}$$

Rounding to two decimal places:

$$\boxed{24.14 \text{ litres}}$$

"Exactly fill the prism" means their volumes are equal.

$$V_{cylinder} = V_{prism}$$

The volume of a cylinder is $V_{cylinder} = \pi r^2 h_{cylinder}$.
We have $V_{prism} = 24142.1356 \text{ cm}^3$ and $h_{cylinder} = 28$ cm.

$$\pi r^2 (28 \text{ cm}) = 24142.1356 \text{ cm}^3$$

$$r^2 = \frac{24142.1356 \text{ cm}^3}{\pi \times 28 \text{ cm}}$$ $$r^2 = \frac{24142.1356}{87.964594}$$ $$r^2 = 274.459069 \text{ cm}^2$$ $$r = \sqrt{274.459069 \text{ cm}^2}$$ $$r = 16.566806 \text{ cm}$$

Rounding to two decimal places:

$$\boxed{16.57 \text{ cm}}$$