249805 has 8 divisors (see below), whose sum is σ = 306432. Its totient is φ = 195408.

The previous prime is 249797. The next prime is 249811. The reversal of 249805 is 508942.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 249805 - 2³ = 249797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 297 + ... + 766.

It is an arithmetic number, because the mean of its divisors is an integer number (38304).

2²⁴⁹⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

249805 is a deficient number, since it is larger than the sum of its proper divisors (56627).

249805 is a wasteful number, since it uses less digits than its factorization.

249805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1115.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 249805 is about 499.8049619602. The cubic root of 249805 is about 62.9796692607.

The spelling of 249805 in words is "two hundred forty-nine thousand, eight hundred five".