Number N = 26 * 55 * 76 * 107; how many factors of N are even numbers?
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Number N = 26 * 55 * 76 * 107; how many factors of N are even numbers?
- A.
1183
- B.
1200
- C.
1050
- D.
540
Attempted by 53 students.
Show answer & explanation
Correct answer: A
Prime factorization: N = 2^6 * 5^5 * 7^6 * 10^7 = 2^(6+7) * 5^(5+7) * 7^6 = 2^13 * 5^12 * 7^6
Total number of factors: (13 + 1) * (12 + 1) * (6 + 1) = 14 * 13 * 7 = 1274
Number of odd factors (exclude the factor 2): (12 + 1) * (6 + 1) = 13 * 7 = 91
Number of even factors: total factors − odd factors = 1274 − 91 = 1183
Answer: 1183