33 is:
the largest positive integer that cannot be expressed as a sum of different triangular numbers.
the smallest odd repdigit that is not a prime number.
the sum of the first four positive factorials.
the sum of the sum of the divisors of the first 6 positive integers.
the sum of three cubes: {\displaystyle 33=8866128975287528^{3}+(-8778405442862239)^{3}+(-2736111468807040)^{3}}{\displaystyle 33=8866128975287528^{3}+(-8778405442862239)^{3}+(-2736111468807040)^{3}}.[1]
equal to the sum of the squares of the digits of its own square in bases 9, 16 and 31.
For numbers greater than 1, this is a rare property to have in more than 1 base.
the smallest integer such that it and the next two integers all have the same number of divisors.
the first member of the first cluster of three semiprimes (33, 34, 35); the next such cluster is 85, 86, 87.
