It is a happy number.
The square root of 100 is 10.
100 is nontrivially palindromic in base 3, base 7 and base 9.
100 is an esthetic number in base 4 and base 9, because in such bases its adjacent digits differ by 1.
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
It is a Leyland number of the form 62 + 26.
It is a Duffinian number.
100 is an undulating number in base 7 and base 9.
It is a plaindrome in base 6, base 8, base 13 and base 15.
It is a nialpdrome in base 5, base 10, base 11, base 12, base 14 and base 16.
100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.
100 is the 10-th square number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 100
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
100 is a wasteful number, since it uses less digits than its factorization.
100 is an odious number, because the sum of its binary digits is odd.
The cubic root of 100 is about 4.6415888336.