1765 has 4 divisors (see below), whose sum is σ = 2124. Its totient is φ = 1408.

The previous prime is 1759. The next prime is 1777. The reversal of 1765 is 5671.

1765 is nontrivially palindromic in base 13.

It is a Cunningham number, because it is equal to 42²+1.

1765 is an esthetic number in base 6, because in such base its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5671 = 53 ⋅107.

It can be written as a sum of positive squares in 2 ways, for example, as 676 + 1089 = 26^2 + 33^2 .

It is a cyclic number.

It is not a de Polignac number, because 1765 - 2⁵ = 1733 is a prime.

It is an Ulam number.

It is a d-powerful number, because it can be written as 1 + 6⁴ + 7³ + 5³ .

It is a Duffinian number.

1765 is an undulating number in base 13.

1765 is a lucky number.

It is a plaindrome in base 8.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 172 + ... + 181.

It is an arithmetic number, because the mean of its divisors is an integer number (531).

It is an amenable number.

1765 is a deficient number, since it is larger than the sum of its proper divisors (359).

1765 is an equidigital number, since it uses as much as digits as its factorization.

1765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358.

The product of its digits is 210, while the sum is 19.

The square root of 1765 is about 42.0119030752. The cubic root of 1765 is about 12.0850440173.

It can be divided in two parts, 176 and 5, that added together give a palindrome (181).

The spelling of 1765 in words is "one thousand, seven hundred sixty-five".