1165 has 4 divisors (see below), whose sum is σ = 1404. Its totient is φ = 928.

The previous prime is 1163. The next prime is 1171. The reversal of 1165 is 5611.

1165 = T₁₀ + T₁₁ + ... + T₁₉.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5611 = 31 ⋅181.

It can be written as a sum of positive squares in 2 ways, for example, as 324 + 841 = 18^2 + 29^2 .

It is a cyclic number.

It is not a de Polignac number, because 1165 - 2¹ = 1163 is a prime.

It is a Smith number, since the sum of its digits (13) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a nialpdrome in base 6 and base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112 + ... + 121.

It is an arithmetic number, because the mean of its divisors is an integer number (351).

It is an amenable number.

1165 is a deficient number, since it is larger than the sum of its proper divisors (239).

1165 is an equidigital number, since it uses as much as digits as its factorization.

1165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238.

The product of its digits is 30, while the sum is 13.

The square root of 1165 is about 34.1320963318. The cubic root of 1165 is about 10.5222506233.

Adding to 1165 its reverse (5611), we get a palindrome (6776).

It can be divided in two parts, 116 and 5, that added together give a palindrome (121).

The spelling of 1165 in words is "one thousand, one hundred sixty-five".