• 900 can be written using four 4's:
The square root of 900 is 30.
900 is nontrivially palindromic in base 14.
900 is an esthetic number in base 9 and base 13, 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 Duffinian number.
900 is an undulating number in base 7 and base 14.
It is a nialpdrome in base 6, base 10, base 12, base 13 and base 15.
900 is a gapful number since it is divisible by the number (90) formed by its first and last digit.
900 is the 30-th square number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 900
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
900 is a wasteful number, since it uses less digits than its factorization.
900 is an evil number, because the sum of its binary digits is even.
The cubic root of 900 is about 9.6548938461.