Number analysis
68
68 is a composite even number that factors as 2^2 × 17.
68 is a composite even number that factors as 2^2 × 17.
The number itself
- Value
- 68
- Digits
- 2
- Digit sum
- 14
- Reversed
- 86
- Palindrome
- No
6 + 8
Digit sum repeated until one digit remains; equals n mod 9 (with 9 for multiples of 9).
Reverses to 86.
Parity and primality
- Parity
- Even
- Prime
- No
- Prime factorisation
- 2^2 × 17
- Squarefree
- No
- Möbius μ(n)
- 0
- Nearest primes
- 67 ← → 71
Divisible by 2.
Composite — it factors as 2^2 × 17.
2 distinct prime factors, 3 with multiplicity.
At least one prime appears squared.
Zero, because a squared prime divides n.
A gap of 4 between them.
Divisors
- Aliquot sum
- 58
- Classification
- Deficient
1, 2, 4, 17, 34, 68
The proper divisors — everything except n itself.
Its proper divisors fall short by 10.
How many integers from 1 to n share no factor with n.
Sums and additive structure
- Sum of two squares
- Yes
- Sum of three squares
- Yes
- Sum of four squares
- Yes
- Goldbach pair
- 7 + 61
2² + 8² = 68
Legendre's three-square theorem allows it.
Lagrange's four-square theorem: every non-negative integer is, without exception.
The smallest pair of primes summing to n. Goldbach’s conjecture says one always exists; it remains unproven.
Shapes and sequences
- Figurate shapes
- None
Not triangular, square, pentagonal, hexagonal, cubic, Fibonacci, Lucas, Catalan, factorial or a power of two.
Digit curiosities
- Happy number
- Yes
- Harshad number
- No
- Collatz trajectory
- 14 steps to 1
Repeatedly summing the squares of its digits reaches 1.
Not divisible by its digit sum 14.
Peaks at 68 along the way.
Written other ways
- Binary
- 1000100
- Octal
- 104
- Hexadecimal
- 44
- Base 36
- 1W
- Roman numerals
- LXVIII
- In words
- sixty-eight
- Scientific notation
- 6.8 × 10^1
Is 68 a prime number?
Composite — it factors as 2^2 × 17.
Nearby numbers
Other numeral systems
Beyond the bases and Roman numerals above, these notations write 68 their own way.
- Greek (alphabetic)
- ΞΗʹ
- Babylonian cuneiform
- 𒐕𒐜
- Tamil
- ௬௰௮
References
Further reading: Wikipedia · Wikidata
Notations, naming and the links above come from Wikidata, whose structured data is dedicated to the public domain under CC0-1.0. Retrieved 2026-10-07.