Divisors of 55: All 4 Factors
Quick Answer
55 has 4 divisors (factors): 1, 5, 11, 55.
Sum: 72.
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 55
The number 55 has 4 divisors:
1, 5, 11, 55
Divisor Pairs of 55
Each pair multiplies to 55:
| Factor 1 | × | Factor 2 | = | Product |
|---|---|---|---|---|
| 1 | × | 55 | = | 55 |
| 5 | × | 11 | = | 55 |
Number of Divisors
The number 55 has 4 divisors, written as τ(55) = 4 in number theory.
Sum of Divisors
σ(55) = 1 + 5 + 11 + 55 = 72
Prime Factorization of 55
Properties of 55
- 55 is composite.
- 55 is not a perfect square.
- Number of divisors: 4.
- Sum of divisors: 72.
Common Divisors with Another Number?
Looking for the divisors that 55 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 55
An efficient way to find divisors uses the complementary pair trick: check each integer i from 1 to √55 ≈ 7.42. If i divides 55, then both i and 55/i are divisors.
- 1 divides 55 (55 ÷ 1 = 55) → pair (1, 55)
- 5 divides 55 (55 ÷ 5 = 11) → pair (5, 11)
- Collect all unique values: {1, 5, 11, 55} — total 4 divisors.
- Sum: 1 + 5 + 11 + 55 = 72.
Related Operations for 55
- Multiples of 55 — "outward" complement; M is a multiple of 55 ⇔ 55 is a divisor of M
- 55 Prime Factorization — decompose into prime building blocks
- Find GCF of 55 and another number
- Find LCM of 55 and another number
- Is 55 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