865243 has 4 divisors (see below), whose sum is σ = 871200. Its totient is φ = 859288.

The previous prime is 865231. The next prime is 865247. The reversal of 865243 is 342568.

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

It is a cyclic number.

It is not a de Polignac number, because 865243 - 2⁵ = 865211 is a prime.

It is a Duffinian number.

865243 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (865247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2755 + ... + 3052.

It is an arithmetic number, because the mean of its divisors is an integer number (217800).

2⁸⁶⁵²⁴³ is an apocalyptic number.

865243 is a deficient number, since it is larger than the sum of its proper divisors (5957).

865243 is a wasteful number, since it uses less digits than its factorization.

865243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5956.

The product of its digits is 5760, while the sum is 28.

The square root of 865243 is about 930.1843903227. The cubic root of 865243 is about 95.2897157579.

It can be divided in two parts, 86 and 5243, that added together give a square (5329 = 73²).

The spelling of 865243 in words is "eight hundred sixty-five thousand, two hundred forty-three".