161 is nontrivially palindromic in base 10.
161 is an esthetic number in base 15, because in such base it adjacent digits differ by 1.
It is a semiprime because it is the product of two primes.
It is a cyclic number.
It is a Cullen number, since it is equal to 5×25+1.
It is an alternating number because its digits alternate between odd and even.
It is a Duffinian number.
161 is an undulating number in base 10.
It is a plaindrome in base 3, base 9, base 11, base 12 and base 15.
It is a nialpdrome in base 7, base 13, base 14 and base 16.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 161.
It is an amenable number.
161 is an equidigital number, since it uses as much as digits as its factorization.
161 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 30.
The square root of 161 is about 12.6885775404. The cubic root of 161 is about 5.4401218254.
The spelling of 161 in words is "one hundred sixty-one", and is thus an aban number.