1865 has 4 divisors (see below), whose sum is σ = 2244. Its totient is φ = 1488.

The previous prime is 1861. The next prime is 1867. The reversal of 1865 is 5681.

1865 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.

It can be written as a sum of positive squares in 2 ways, for example, as 841 + 1024 = 29^2 + 32^2 .

It is a cyclic number.

It is not a de Polignac number, because 1865 - 2² = 1861 is a prime.

It is a Duffinian number.

It is a plaindrome in base 6 and base 11.

It is a nialpdrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (1861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 182 + ... + 191.

It is an arithmetic number, because the mean of its divisors is an integer number (561).

It is an amenable number.

1865 is a deficient number, since it is larger than the sum of its proper divisors (379).

1865 is an equidigital number, since it uses as much as digits as its factorization.

1865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378.

The product of its digits is 240, while the sum is 20.

The square root of 1865 is about 43.1856457634. The cubic root of 1865 is about 12.3090993984.

It can be divided in two parts, 186 and 5, that added together give a palindrome (191).

The spelling of 1865 in words is "one thousand, eight hundred sixty-five".