Factors of 81

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Factors of

What are the Factors of 81?

Answer

Factors of 81:
1, 3, 9, 27, 81

(number 81 has 5 factors)

Factor Pairs of 81

A Factor Pair of number 81 is a combination of two factors which can be multiplied together to equal 81.

List of all possible Factor Pairs of 81:

  • 1 × 81 = 81
  • 3 × 27 = 81
  • 9 × 9 = 81

How to find the Factors of 81

Divide 81 by every whole number from 1 up to 9. Each division without a remainder gives a factor and its pair. There is no point going further: 10 × 10 = 100 is already greater than 81, so any larger divisor would pair with a smaller one you have already checked.

  • 81 ÷ 1 = 81 — factors 1 and 81
  • 81 ÷ 2 — remainder 1, not a factor
  • 81 ÷ 3 = 27 — factors 3 and 27
  • 81 ÷ 4 — remainder 1, not a factor
  • 81 ÷ 5 — remainder 1, not a factor
  • 81 ÷ 6 — remainder 3, not a factor
  • 81 ÷ 7 — remainder 4, not a factor
  • 81 ÷ 8 — remainder 1, not a factor
  • 81 ÷ 9 = 9 — factor 9, paired with itself

Why 81 has exactly 5 factors

The count follows from the prime factorization: add 1 to each exponent and multiply. Counting the divisors this way needs no trial division at all, however large the number is.

81 = 34

(4 + 1) = 5

Step-by-step factorization: Prime factors of 81.

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About "Factors of a Number" Calculator

This calculator will help you find all factors of a given number. For example, it can help you find out what are the Factors of 81? (The answer is: 1, 3, 9, 27, 81). Pick the number (e.g. '81'). After that hit the 'Find' button.
The Factors of a number are numbers that divides initial number evenly, with no remainder
"Factors of a Number" Calculator

Factors of

Factors Table

NumberFactors
661, 2, 3, 6, 11, 22, 33, 66
671, 67
681, 2, 4, 17, 34, 68
691, 3, 23, 69
701, 2, 5, 7, 10, 14, 35, 70
711, 71
721, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
731, 73
741, 2, 37, 74
751, 3, 5, 15, 25, 75
761, 2, 4, 19, 38, 76
771, 7, 11, 77
781, 2, 3, 6, 13, 26, 39, 78
791, 79
801, 2, 4, 5, 8, 10, 16, 20, 40, 80
811, 3, 9, 27, 81
821, 2, 41, 82
831, 83
841, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84
851, 5, 17, 85
861, 2, 43, 86
871, 3, 29, 87
881, 2, 4, 8, 11, 22, 44, 88
891, 89
901, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
911, 7, 13, 91
921, 2, 4, 23, 46, 92
931, 3, 31, 93
941, 2, 47, 94
951, 5, 19, 95

FAQ

What are the Factors of 81?

Factors of 81: 1, 3, 9, 27, 81

How many factors does 81 have?

Number 81 has 5 factors

How many Factor Pairs does 81 have?

Number 81 has 3 factor pairs

See Also