243659 has 4 divisors (see below), whose sum is σ = 262416. Its totient is φ = 224904.

The previous prime is 243647. The next prime is 243671. The reversal of 243659 is 956342.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 956342 = 2 ⋅478171.

It is an interprime number because it is at equal distance from previous prime (243647) and next prime (243671).

It is a cyclic number.

It is not a de Polignac number, because 243659 - 2⁴ = 243643 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243259) 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, 9359 + ... + 9384.

It is an arithmetic number, because the mean of its divisors is an integer number (65604).

2²⁴³⁶⁵⁹ is an apocalyptic number.

243659 is a deficient number, since it is larger than the sum of its proper divisors (18757).

243659 is a wasteful number, since it uses less digits than its factorization.

243659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18756.

The product of its digits is 6480, while the sum is 29.

The square root of 243659 is about 493.6182735677. The cubic root of 243659 is about 62.4588742781.

The spelling of 243659 in words is "two hundred forty-three thousand, six hundred fifty-nine".