78865 has 4 divisors (see below), whose sum is σ = 94644. Its totient is φ = 63088.

The previous prime is 78857. The next prime is 78877. The reversal of 78865 is 56887.

78865 is nontrivially palindromic in base 6.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56887 = 163 ⋅349.

It can be written as a sum of positive squares in 2 ways, for example, as 37249 + 41616 = 193^2 + 204^2 .

It is a cyclic number.

It is not a de Polignac number, because 78865 - 2³ = 78857 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78865.

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, 7882 + ... + 7891.

It is an arithmetic number, because the mean of its divisors is an integer number (23661).

2⁷⁸⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

78865 is a deficient number, since it is larger than the sum of its proper divisors (15779).

78865 is a wasteful number, since it uses less digits than its factorization.

78865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15778.

The product of its digits is 13440, while the sum is 34.

The square root of 78865 is about 280.8291295432. The cubic root of 78865 is about 42.8839488386.

The spelling of 78865 in words is "seventy-eight thousand, eight hundred sixty-five".