243591 has 4 divisors (see below), whose sum is σ = 324792. Its totient is φ = 162392.

The previous prime is 243589. The next prime is 243613. The reversal of 243591 is 195342.

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 243591 - 2¹ = 243589 is a prime.

It is a D-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 243591.

It is not an unprimeable number, because it can be changed into a prime (243521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40596 + ... + 40601.

It is an arithmetic number, because the mean of its divisors is an integer number (81198).

2²⁴³⁵⁹¹ is an apocalyptic number.

243591 is a deficient number, since it is larger than the sum of its proper divisors (81201).

243591 is an equidigital number, since it uses as much as digits as its factorization.

243591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81200.

The product of its digits is 1080, while the sum is 24.

The square root of 243591 is about 493.5493896258. The cubic root of 243591 is about 62.4530634268.

The spelling of 243591 in words is "two hundred forty-three thousand, five hundred ninety-one".