68 (number)
From Halbeeg, the open encyclopedia · Af-Soomaali
77 languages
68 is a natural number that follows 67 and precedes 69. It is an even number, meaning it can be divided by two without remainder. In Roman numerals it is written LXVIII.
68 is not a prime number, because it has divisors other than 1 and itself. Its complete divisors are 1, 2, 4, 17, 34, and 68.
Mathematical properties
The prime factorization of 68 is 2² × 17. It therefore has six divisors in total. The sum of its divisors excluding itself is 58 (1+2+4+17+34), which is less than 68—for this reason 68 is classified as a deficient number.
In binary notation 68 is written as 1000100. In hexadecimal it is 44. Additionally 68 equals 64 + 4, which is the sum of two perfect squares (8² + 2²).
68 is known as a happy number: when the squares of its digits are successively added—6²+8² = 100, then 1²+0²+0² = 1—the sequence terminates at 1.
General uses
68 is used like any other number: for counting, measurement, years (for example 1968 is sometimes abbreviated as "68"), and in phone numbers or vehicle registration plates. It also appears in the names of historical events designated by their year.