Divisors of 91: All 4 Factors
Quick Answer
91 has 4 divisors (factors): 1, 7, 13, 91.
Sum: 112.
Divisors (Factors) Calculator
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 91
The number 91 has 4 divisors:
1, 7, 13, 91
Divisor Pairs of 91
Each pair multiplies to 91:
| Factor 1 | × | Factor 2 | = | Product |
|---|---|---|---|---|
| 1 | × | 91 | = | 91 |
| 7 | × | 13 | = | 91 |
Number of Divisors
The number 91 has 4 divisors, written as τ(91) = 4 in number theory.
Sum of Divisors
σ(91) = 1 + 7 + 13 + 91 = 112
Prime Factorization of 91
Properties of 91
- 91 is composite.
- 91 is not a perfect square.
- Number of divisors: 4.
- Sum of divisors: 112.
Common Divisors with Another Number?
Looking for the divisors that 91 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 91
An efficient way to find divisors uses the complementary pair trick: check each integer i from 1 to √91 ≈ 9.54. If i divides 91, then both i and 91/i are divisors.
- 1 divides 91 (91 ÷ 1 = 91) → pair (1, 91)
- 7 divides 91 (91 ÷ 7 = 13) → pair (7, 13)
- Collect all unique values: {1, 7, 13, 91} — total 4 divisors.
- Sum: 1 + 7 + 13 + 91 = 112.
Nearby Examples
Related Operations for 91
- Multiples of 91 — "outward" complement; M is a multiple of 91 ⇔ 91 is a divisor of M
- 91 Prime Factorization — decompose into prime building blocks
- Find GCF of 91 and another number
- Find LCM of 91 and another number
- Is 91 a perfect square? (odd divisor count ⇔ yes)
See also our tables of divisors:
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.
Divisors Calculation Examples
Find all divisors of these numbers:
Related Calculators
- Multiples of a Number — "outward" complement
- Prime Factorization — product of prime divisors
- Greatest Common Factor (GCF) — largest common divisor of 2+ numbers
- Least Common Multiple (LCM) — smallest common multiple
- Is N a Perfect Square? — odd divisor count check