Numbers / 428

The Number 428

428 is composite: factorization 2^2 × 107. That gives 428 exactly 6 divisors: 1, 2, 4, 107, 214, 428. 428's proper divisors total just 328, 100 short of 428, the deficient case most of 428's neighbors share too. 428 has a digit sum of 14; for 428, the digital root works out to 5. 428: 2, 4 all divide 428 evenly, out of 2-12. 428 is 110101100 in binary and 1AC in hex; as a Roman numeral it's CDXXVIII.