249865 has 24 divisors (see below), whose sum is σ = 383040. Its totient is φ = 153120.

The previous prime is 249863. The next prime is 249871. The reversal of 249865 is 568942.

It is a happy number.

It is not a de Polignac number, because 249865 - 2¹ = 249863 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 249865.

It is not an unprimeable number, because it can be changed into a prime (249863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4206 + ... + 4264.

It is an arithmetic number, because the mean of its divisors is an integer number (15960).

2²⁴⁹⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

249865 is a deficient number, since it is larger than the sum of its proper divisors (133175).

249865 is a wasteful number, since it uses less digits than its factorization.

249865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93 (or 82 counting only the distinct ones).

The product of its digits is 17280, while the sum is 34.

The square root of 249865 is about 499.8649817701. The cubic root of 249865 is about 62.9847111636.

It can be divided in two parts, 24 and 9865, that added together give a palindrome (9889).

The spelling of 249865 in words is "two hundred forty-nine thousand, eight hundred sixty-five".