A pharmacist is making the following compounded prescription. If the specific gravity of polyethylene glycol 1450 is 1.21, how many milliliters are needed for the prescription?
(Answer must be numeric; no units or commas; include a leading zero when the answer is less than 1; round the final answer to the nearest TENTH.)

Estradiol 0.25 mg and Estrone 0.25 mg Troches
Estradiol = 6 mg
Estrone = 6 mg
Stevia powder extract = 500 mg
Silica gel, micronized = 240 mg
Flavor (mild) = qs
Polyethylene glycol 1450 = 23.5 g