10000000000000000000:100000000000000000

Let's simplify the ratio:

\[ \frac{10,000,000,000,000,000,000}{100,000,000,000,000,000} \]

Both numbers can be divided by 100,000,000,000,000,000 (which is \( 10^{14} \)):

\[ \frac{10,000,000,000,000,000,000 ÷ 10^{14}}{100,000,000,000,000,000 ÷ 10^{14}} = \frac{10^{19} ÷ 10^{14}}{10^{14} ÷ 10^{14}} = \frac{10^{5}}{1} = 100,000 \]

Answer: The simplified ratio is 100,000:1.