The sum of the prime factors of 1729 is
13
19
32
39
Step 1: Try dividing 1729 by small primes.
Not by 2, because 1729 is odd.
Not by 3, because \(1+7+2+9 = 19\) (not a multiple of 3).
Not by 5, because the last digit is 9 (not 0 or 5).
Step 2: Try 7.
\(1729 \div 7 = 247\)
So, \(1729 = 7 \times 247\).
Step 3: Factor 247.
Not by 2, 3, or 5 (same checks as before).
Check 7: \(7 \times 35 = 245\), so not exact.
Check 11: \(11 \times 22 = 242\), so not exact.
Check 13: \(247 \div 13 = 19\)
So, \(247 = 13 \times 19\).
Step 4: Confirm primes.
13 and 19 are both prime numbers.
Step 5: Write the prime factorization.
\(1729 = 7 \times 13 \times 19\)
Step 6: Add the prime factors.
\(7 + 13 + 19 = 39\)
Answer: 39 (Option D).