651 is nontrivially palindromic in base 5 and base 6.
651 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
651 is an esthetic number in base 5, because in such base it adjacent digits differ by 1.
It is a sphenic number, since it is the product of 3 distinct primes.
It is the 26-th Hogben number.
It is a Duffinian number.
651 is an undulating number in base 5.
651 is a lucky number.
It is a plaindrome in base 14 and base 16.
It is a nialpdrome in base 10 and base 11.
It is a congruent number.
651 is a wasteful number, since it uses less digits than its factorization.
651 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 41.
The square root of 651 is about 25.5147016443. The cubic root of 651 is about 8.6668310291. Note that the first 3 decimals are identical.
The spelling of 651 in words is "six hundred fifty-one", and is thus an aban number.