Show numerical properties of 4
We start by listing out divisors for 4
Divisor | Divisor Math |
---|---|
1 | 4 ÷ 1 = 4 |
2 | 4 ÷ 2 = 2 |
Positive Numbers > 0
Since 4 ≥ 0 and it is an integer
4 is a positive number
Positive numbers including 0
with no decimal or fractions
Since 4 ≥ 0 and it is an integer
4 is a whole number
Since 4 has divisors other than 1 and itself
it is a composite number
Calculate divisor sum D
If D = N, then it's perfect
If D > N, then it's abundant
If D < N, then it's deficient
Divisor Sum = 1 + 2
Divisor Sum = 3
Since our divisor sum of 3 < 4
4 is a deficient number!
A number is even if it is divisible by 2
If not divisible by 2, it is odd
2 = | 4 |
2 |
Since 2 is an integer, 4 is divisible by 2
it is an even number
This can be written as A(4) = Even
Get binary expansion
If binary has even amount 1's, then it's evil
If binary has odd amount 1's, then it's odious
4 to binary = 100
There are 1 1's, 4 is an odious number
Can you stack numbers in a pyramid?
Each row above has one item less than the row before it
Using a bottom row of 3 items, we cannot form a pyramid
4 is not triangular
Is there an integer m such that n = m(m + 1)
No integer m exists such that m(m + 1) = 4
4 is not rectangular
Does n2 ends with n
42 = 4 x 4 = 16
Since 16 does not end with 4
it is not automorphic (curious)
Do the digits of n alternate in the form abab
Since 4 < 100
We only perform the test on numbers > 99
Is there a number m such that m2 = n?
22 = 4
Since 4 is the square of 2
4 is a square
Is there a number m such that m3 = n
13 = 1 and 23 = 8 ≠ 4
Therefore, 4 is not a cube
Is the number read backwards equal to the number?
The number read backwards is 4
Since 4 is the same backwards and forwards
it is a palindrome
Is it both prime and a palindrome
From above, since 4 is not both prime and a palindrome
it is NOT a palindromic prime
A number is repunit if every digit is equal to 1
Since there is at least one digit in 4 ≠ 1
then it is NOT repunit
Does 2n contain the consecutive digits 666?
24 = 16
Since 24 does not have 666
4 is NOT an apocalyptic power
It satisfies the form:
n(3n - 1) | |
2 |
2(3(2 - 1) | |
2 |
2(6 - 1) | |
2 |
2(5) | |
2 |
10 | |
2 |
5 ← Since this does not equal 4
this is NOT a pentagonal number
1(3(1 - 1) | |
2 |
1(3 - 1) | |
2 |
1(2) | |
2 |
2 | |
2 |
1 ← Since this does not equal 4
this is NOT a pentagonal number
Is there an integer m such that n = m(2m - 1)
No integer m exists such that m(2m - 1) = 4
Therefore 4 is not hexagonal
Is there an integer m such that:
m = | n(5n - 3) |
2 |
No integer m exists such that m(5m - 3)/2 = 4
Therefore 4 is not heptagonal
Is there an integer m such that n = m(3m - 3)
No integer m exists such that m(3m - 2) = 4
Therefore 4 is not octagonal
Is there an integer m such that:
m = | n(7n - 5) |
2 |
No integer m exists such that m(7m - 5)/2 = 4
Therefore 4 is not nonagonal
Tetrahederal numbers satisfy the form:
n(n + 1)(n + 2) | |
6 |
2(2 + 1)(2 + 2) | |
6 |
2(3)(4) | |
6 |
24 | |
6 |
4 ← Since this equals 4
This is a tetrahedral (Pyramidal)number
Is equal to the square sum of it's m-th powers of its digits
4 is a 1 digit number, so m = 1
Square sum of digitsm = 41
Square sum of digitsm = 4
Square sum of digitsm = 4
Since 4 = 4
4 is narcissistic (plus perfect)
Cn = | 2n! |
(n + 1)!n! |
C3 = | (2 x 3)! |
3!(3 + 1)! |
Using our factorial lesson
C3 = | 6! |
3!4! |
C3 = | 720 |
(6)(24) |
C3 = | 720 |
144 |
C3 = 5
Since this does not equal 4
This is NOT a Catalan number
C2 = | (2 x 2)! |
2!(2 + 1)! |
Using our factorial lesson
C2 = | 4! |
2!3! |
C2 = | 24 |
(2)(6) |
C2 = | 24 |
12 |
C2 = 2
Since this does not equal 4
This is NOT a Catalan number