133 (number)

133 (one hundred [and] thirty-three) is a natural number. It is after 132 and before 134.

 In mathematics 
The sum of 133's proper divisors is equal to φ(n).

133 is an octagonal number, a Harshad number and a happy number.

In base 11(111) and base 18(77), 133 is a repdigit(a natural number that has only one type of digit).

133 is a semiprime number number(a product of 7 and 19). 7 and 19 are both Gaussian primes. This means that 133 is also a Blum integer

 In other fields 
133 is also:

 The atomic number of the element called untritrium.
 Xenon-133 is an isotope of xenon.
 133 is the police emergency telephone number in Chile
 "133" is the name of a David Guetta song, from the album Just a Little More Love 
 In Austria, the phone number for the police.

 References 

Category:Integers