851 is nontrivially palindromic in base 16.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 158 = 2 ⋅79.
It is a cyclic number.
It is a Duffinian number.
851 is an undulating number in base 6 and base 16.
It is a plaindrome in base 9, base 12, base 14 and base 15.
It is a nialpdrome in base 10.
851 is a wasteful number, since it uses less digits than its factorization.
851 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 60.
The square root of 851 is about 29.1719042916. The cubic root of 851 is about 9.4763956934.
The spelling of 851 in words is "eight hundred fifty-one", and is thus an aban number.