Number
78
- Positive
- Even
- Composite
- 2 digits
78 is an even 2-digit integer and a composite number. It has 8 divisors and a digital root of 6.
Number properties
ParityEvendivisible by 2
SignPositive
PrimalityComposite
Absolute value78
Digit count2
Digit sum15
Digital root6repeated digit sum
PalindromicNoreads differently backwards
Triangular numberYes, the 12th triangular number
Happy numberNosquared-digit sums reach 1
Harshad numberNodivisible by its own digit sum
Factors & divisors
Prime factorisation2 × 3 × 13
Distinct prime factors32, 3, 13
Number of divisors8
Sum of divisors σ(n)168
Aliquot sum90sum of the proper divisors
ClassificationAbundantthe aliquot sum exceeds the number
Euler's totient φ(n)24integers below n that share no factor with it
SquarefreeYesno repeated prime factor
All divisors1, 2, 3, 6, 13, 26, 39, 788 in total
Arithmetic
Representations
Decimal78
Binary10011107 bits
Octal116
Hexadecimal4E
Base 3626
Roman numeralLXXVIII
In wordsseventy-eight
Ordinalseventy-eighth
Scientific notation7.8 × 10^1
Engineering notation78
Nearest landmarks
Powers & multiples
78 to the power 26,084
78 to the power 3474,552
78 to the power 437,015,056
78 to the power 52,887,174,368
First ten multiples78, 156, 234, 312, 390, 468, 546, 624, 702, 780
Powers of twoBetween 2^6 (64) and 2^7 (128)
Divisibility tests
Divisible by 2Yes
Divisible by 3Yes
Divisible by 4No, remainder 2
Divisible by 5No, remainder 3
Divisible by 6Yes
Divisible by 7No, remainder 1
Divisible by 8No, remainder 6
Divisible by 9No, remainder 6
Divisible by 10No, remainder 8
Divisible by 11No, remainder 1
Divisible by 12No, remainder 6
Divisible by 100No, remainder 78
Collatz (3n + 1) trajectory
Steps to reach 135the total stopping time
Reaches 1Yesthe Collatz conjecture says every positive integer does, but it is unproven
First steps78 → 39 → 118 → 59 → 178 → 89 → 268 → 134 → 67 → 202 → …
Last steps… → 5 → 16 → 8 → 4 → 2 → 1
As a percentage & fraction
As a percentage7,800%
78% as a decimal0.78
78% of 10078
78% of 1,000780
As a fraction of 10078/100
Read another way
Keep nerding
Every link below is a page Nerdulator can generate from what it already knows about this value.
Derived from 78
Other readings
Nerdulate something else
Nothing in mind? Surprise me · today’s page