• D.H.Lehmer has conjectured that 163 is the largest
prime that can be written as a sum of 3 squares in exactly one
way, 163 = 1^{2} + 9^{2} + 9^{2}.

163 has 2 divisors, whose sum is σ = 164. Its totient is φ = 162.

The previous prime is 157. The next prime is 167. The reversal of 163 is 361.

163 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 163 - 2^{5} = 131 is a prime.

It is an alternating number because its digits alternate between odd and even.

163 is a lucky number.

It is a plaindrome in base 5, base 11, base 12 and base 15.

It is a nialpdrome in base 6, base 7, base 13, base 14 and base 16.

It is a Pierpont prime, being equal to 2^{1} ⋅ 3^{4} + 1.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81 + 82.

It is an arithmetic number, because the mean of its divisors is an integer number (82).

163 is a deficient number, since it is larger than the sum of its proper divisors (1).

163 is an equidigital number, since it uses as much as digits as its factorization.

163 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18, while the sum is 10.

The square root of 163 is about 12.7671453348. The cubic root of 163 is about 5.4625555713.

Subtracting from 163 its sum of digits (10), we obtain a triangular number (153 = T_{17}).

Adding to 163 its product of digits (18), we get a palindrome (181).

It can be divided in two parts, 1 and 63, that added together give a 6-th power (64 = 2^{6}).

The spelling of 163 in words is "one hundred sixty-three", and thus it is an aban number.

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