9865 has 4 divisors (see below), whose sum is σ = 11844. Its totient is φ = 7888.

The previous prime is 9859. The next prime is 9871. The reversal of 9865 is 5689.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (9859) and next prime (9871).

It can be written as a sum of positive squares in 2 ways, for example, as 2809 + 7056 = 53^2 + 84^2 .

It is a cyclic number.

It is not a de Polignac number, because 9865 - 2³ = 9857 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a nialpdrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 982 + ... + 991.

It is an arithmetic number, because the mean of its divisors is an integer number (2961).

2⁹⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

9865 is a deficient number, since it is larger than the sum of its proper divisors (1979).

9865 is a wasteful number, since it uses less digits than its factorization.

9865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1978.

The product of its digits is 2160, while the sum is 28.

The square root of 9865 is about 99.3227063667. The cubic root of 9865 is about 21.4469577645.

The spelling of 9865 in words is "nine thousand, eight hundred sixty-five".