243491 has 4 divisors (see below), whose sum is σ = 257832. Its totient is φ = 229152.

The previous prime is 243487. The next prime is 243517. The reversal of 243491 is 194342.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 194342 = 2 ⋅97171.

It is a cyclic number.

It is not a de Polignac number, because 243491 - 2² = 243487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 243491.

It is not an unprimeable number, because it can be changed into a prime (243401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7145 + ... + 7178.

It is an arithmetic number, because the mean of its divisors is an integer number (64458).

2²⁴³⁴⁹¹ is an apocalyptic number.

243491 is a deficient number, since it is larger than the sum of its proper divisors (14341).

243491 is a wasteful number, since it uses less digits than its factorization.

243491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14340.

The product of its digits is 864, while the sum is 23.

The square root of 243491 is about 493.4480722427. The cubic root of 243491 is about 62.4445160925. Note that the first 3 decimals are identical.

The spelling of 243491 in words is "two hundred forty-three thousand, four hundred ninety-one".