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Number (or sum) of divisors from the prime factorisation

This type of question, asked 8 times: CDS 2 2018, CDS 2 2020, CDS 1 2022, CDS 2 2022, CDS 1 2023, CDS 2 2024, CDS 1 2025, CDS 1 2026. All 8 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    CDS 2 2018

    7
    The number of divisors of the number 38808, exclusive of the divisors 1 and itself, is

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  2. Question 2

    CDS 2 2020

    19
    Let d(n)d(n) denote the number of positive divisors of a positive integer nn. Which of the following are correct ? 1. d(5)=d(11)d(5) = d(11) 2. d(5)⋅d(11)=d(55)d(5) \cdot d(11) = d(55) 3. d(5)+d(11)=d(16)d(5) + d(11) = d(16) Select the correct answer using the code given below :

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  3. Question 3

    CDS 1 2022

    35
    What is the number of divisors of 1000 (excluding 1 and 1000)?

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  4. Question 4

    CDS 2 2022

    21
    Consider the number N=126×38×53N = 12^6 \times 3^8 \times 5^3. Which of the following statements is/are correct ? 1. The number of odd factors of N is 60. 2. The number of even factors of N is 720. Select the correct answer using the code given below :

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  5. Question 5

    CDS 1 2023

    22
    Consider the following statements in respect of all factors of 360 : 1. The number of factors is 24. 2. The sum of all factors is 1170. Which of the above statements is/are correct?

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  6. Question 6

    CDS 2 2024

    31
    A 4-digit number NN has exactly 15 distinct divisors. What is the total number of distinct divisors of N2N^2 ?

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  7. Question 7

    CDS 1 2025

    48
    What is the number of factors of 243−163−8324^3 - 16^3 - 8^3 ?

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  8. Question 8

    CDS 1 2026

    27
    What is the sum of all the divisors of 256 ?

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