11865 has 16 divisors (see below), whose sum is σ = 21888. Its totient is φ = 5376.

The previous prime is 11863. The next prime is 11867. The reversal of 11865 is 56811.

It is an interprime number because it is at equal distance from previous prime (11863) and next prime (11867).

It is not a de Polignac number, because 11865 - 2¹ = 11863 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

11865 is a lucky number.

It is a plaindrome in base 14.

It is a zygodrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (11863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49 + ... + 161.

It is an arithmetic number, because the mean of its divisors is an integer number (1368).

2¹¹⁸⁶⁵ is an apocalyptic number.

11865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

11865 is a deficient number, since it is larger than the sum of its proper divisors (10023).

11865 is a wasteful number, since it uses less digits than its factorization.

11865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128.

The product of its digits is 240, while the sum is 21.

The square root of 11865 is about 108.9265807781. The cubic root of 11865 is about 22.8081073046.

11865 divided by its sum of digits (21) gives a palindrome (565).

The spelling of 11865 in words is "eleven thousand, eight hundred sixty-five".