38 (number)

• 38! − 1 yields 523022617466601111760007224100074291199999999 which is the 16th factorial prime.[1]
• There is no answer to the equation φ(x) = 38, making 38 a nontotient.[2]
• 38 is the sum of the squares of the first three primes.
• 37 and 38 are the first pair of consecutive positive integers not divisible by any of their digits.
• 38 is the largest even number which cannot be written as the sum of two odd composite numbers.
• The sum of each row of the only non-trivial (order 3) magic hexagon is 38.[3]

• The atomic number of strontium

Ishihara test: Most people will see the number 38, but people with red-green color blindness might see 88 instead.

Thirty-eight is also:

• The 38th parallel north is the pre-Korean War boundary between North Korea and South Korea.[5]
• The number of slots on an American roulette wheel (0, 00, and 1 through 36; European roulette does not use the 00 slot and has only 37 slots)
• The Ishihara test is a color vision test consisting of 38 pseudoisochromatic plates.[6]
• A "38" is often the name for a snub nose .38 caliber revolver.
• The 38 class is the most famous class of steam locomotive used in New South Wales
• Gerald Ford, 38th President of the United States
• Arnold Schwarzenegger, 38th Governor of California, most recent Republican governor of California, and the second governor to be born outside of the United States
• Cats have a total of 38 chromosomes in their genome.
• Number used by Zane Smith and Front Row Motorsports to win the 2022 NASCAR Camping World Truck Series championship.

• List of highways numbered 38