• 210 can be written using four 4's:
It is a primorial, being the product of the first 4 primes.
210 is nontrivially palindromic in base 11.
210 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.
210 is an esthetic number in base 3 and base 10, 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.
210 is an idoneal number.
It is an alternating number because its digits alternate between even and odd.
210 is an undulating number in base 11.
210 is strictly pandigital in base 4.
It is a Curzon number.
It is a straight-line number, since its digits are in arithmetic progression.
It is a plaindrome in base 12.
It is a nialpdrome in base 6, base 7, base 8, base 10, base 14, base 15 and base 16.
It is a congruent number.
210 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
210 is a wasteful number, since it uses less digits than its factorization.
210 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 17.
The square root of 210 is about 14.4913767462. The cubic root of 210 is about 5.9439219528.
Adding to 210 its reverse (12), we get a palindrome (222).