Math Wiki

5 is the integer the proceeds 4 and preceeds 6. It is a Fermat composite number. A number is divisible by 5 if the last digit is 0 or 5.  5 is also the 4th number in the fibonacci sequence. It is the only known odd untouchable number.

properties[]

  • The smallest odd composite number
  • The larger of the only 2 composite numbers that trick the Fermat primality test for every base including Coprime ones. The other one is 2.
  • The larger of the only 2 composite numbers that yield mersene primes. The other one is 2.

Divisors[]

1, 5