Divisors of 1521: All 9 Factors

Quick Answer

1521 has 9 divisors (factors): 1, 3, 9, 13, 39, 117, 169, 507, 1521.

Sum: 2379.  1521 is a perfect square (√1521 = 39).

Divisors (Factors) Calculator


  Ex.: 12, 36, 100, 1024, 1728, etc.
9 divisors
1, 3, 9, 13, 39, 117, 169, 507, 1521

Use the calculator above to find all divisors (also called factors) of any positive integer up to 4,782,969. Beyond the divisor list, this tool also shows divisor pairs, the sum and count of divisors, prime factorization, and number properties (prime, perfect square, perfect number).

All Divisors of 1521

The number 1521 has 9 divisors:

1,  3,  9,  13,  39,  117,  169,  507,  1521

Divisor Pairs of 1521

Each pair multiplies to 1521:

Factor 1×Factor 2=Product
1×1521=1521
3×507=1521
9×169=1521
13×117=1521
39×39=1521

Note: the last pair has identical factors (39 × 39) because 1521 is a perfect square.

Number of Divisors

The number 1521 has 9 divisors, written as τ(1521) = 9 in number theory.

Notice: 1521 has an odd number of divisors — this means 1521 is a perfect square (√1521 = 39).

Sum of Divisors

σ(1521) = 1 + 3 + 9 + 13 + 39 + 117 + 169 + 507 + 1521 = 2379

Properties of 1521

  • 1521 is composite.
  • 1521 is a perfect square (√1521 = 39).
  • Number of divisors: 9.
  • Sum of divisors: 2379.

Common Divisors with Another Number?

Looking for the divisors that 1521 shares with another number? Use our Greatest Common Factor (GCF) calculator — it finds all common divisors and the largest one.

Step-by-Step: How to Find the Divisors of 1521

An efficient way to find divisors uses the complementary pair trick: check each integer i from 1 to √1521 ≈ 39.00. If i divides 1521, then both i and 1521/i are divisors.

  1. 1 divides 1521 (1521 ÷ 1 = 1521) → pair (1, 1521)
  2. 3 divides 1521 (1521 ÷ 3 = 507) → pair (3, 507)
  3. 9 divides 1521 (1521 ÷ 9 = 169) → pair (9, 169)
  4. 13 divides 1521 (1521 ÷ 13 = 117) → pair (13, 117)
  5. 39 divides 1521 (1521 ÷ 39 = 39) → pair (39, 39)
  6. Collect all unique values: {1, 3, 9, 13, 39, 117, 169, 507, 1521} — total 9 divisors.
  7. Sum: 1 + 3 + 9 + 13 + 39 + 117 + 169 + 507 + 1521 = 2379.

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What Is a Divisor?

A divisor (also called a factor) of a positive integer n is any positive integer d such that n ÷ d has no remainder. In other words, d divides n evenly.

Every positive integer n has at least two divisors: 1 and n itself (with 1 being the trivial case of having only itself). Numbers with exactly 2 divisors are prime; numbers with 3 or more divisors are composite.

Why use this calculator? Beyond just listing divisors, this tool computes the sum σ(n), the count τ(n), prime factorization, divisor pairs (useful for visual learners and factoring problems), and detects whether n is a prime, a perfect square, or a perfect number.

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