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Composite Number

The numbers are broadly classified into two categories on the basis of divisibility:

• Prime Numbers
• Composite Numbers
Prime Numbers are defined as the positive integers that are greater than "1" and are divisible by "1" or itself only. For example: 2, 3, 5, 7, 11, 13, 17, 19 etc.

Here, we shall study in detail about composite numbers.

Composite Numbers
Composite numbers are opposite to the prime numbers. The numbers that are not prime, are categorized as composite numbers. The positive integers which are greater than one and are divisible by at least a number other than 1 and itself, are referred as composite numbers.

In other words, we can say that
x is a composite number if x > 1 and x is fully divided (leaves no remainder) by an integer except for "1" and itself.For example: 4 is said to be a composite number since it is greater than "1" and it is divisible by 2.

List of Composite Numbers
There exists an infinite number of composite numbers. Given below is the list of first hundred composite numbers -

 4 6 8 9 10 12 14 15 16 18 20 21 22 24 25 26 27 28 30 32 33 34 35 36 38 39 40 42 44 45 46 48 49 50 51 52 54 55 56 57 58 60 62 63 64 65 66 68 69 70 72 74 75 76 77 78 80 81 82 84 85 86 87 88 90 91 92 93 94 95 96 98 99 100 102 104 105 106 108 110 111 112 114 115 116 117 118 119 120 121 122 123 124 125 126 128 129 130 132 133

We can conclude few facts about composite numbers summarizing them -

• Composite numbers leave no remainder when divided by at least a number other than 1 and itself.
• There are uncountable or infinite composite numbers.
• Composite number is always a positive integer.
• Non-prime numbers are composite numbers.
• 1 is not a composite number and not even a prime number.
• The smallest composite number is 4.
• An even number greater than 2 is necessarily a composite number, since it would definitely be divisible by 2.
• The numbers ending in 5 and greater than 5 are necessarily composite numbers, since these will be divisible by 5.

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