4 barrels at absolute minimum. 5 at a practical minimum, depending on how tightly packed. - Volume: ~ 74 L (19.6 gal) - 6.5e7 [$] * (0.06943 [in^3/bill] / 10

4 barrels at absolute minimum. 5 at a practical minimum, depending on how tightly packed. - Volume: ~ 74 L (19.6 gal) - 6.5e7 [$] * (0.06943 [in^3/bill] / 100 [$/bill]) = 45129.5 in^3 ~ 195.366 gallons or 739.54 L 195.366 [gal] / 55 [gal/barrel] = 3.5 [barrels] Rule-of-thumb: 1.1 L (0.3 gal) / Mega$ - Weight: ~ 650 kg (1433 lbs) - A $100 bill weighs exactly 1.00 gram, so $65M (MM) weighs 650 kg (1433 lbs). The money in each barrel would weigh at most 183 kg (360 lbs), so a water barrel will work since water would weigh about 45 kg (100 lbs) more. Therefore, sealed money barrels float. Rule-of-thumb: 10 kg (22 lbs) / Mega$ - Other Hazards - Mold, insects (silverfish, etc), mudslides, ground-penetrating radar and federal agents