Numbers / 381

The Number 381

381 is composite: factorization 3 × 127. That gives 381 exactly 4 divisors: 1, 3, 127, 381. 381's proper divisors total just 131, 250 short of 381, the deficient case most of 381's neighbors share too. 381 has a digit sum of 12; for 381, the digital root works out to 3. 381: 3 all divide 381 evenly, out of 2-12. 381 is 101111101 in binary and 17D in hex; as a Roman numeral it's CCCLXXXI.