243405 has 20 divisors (see below), whose sum is σ = 437052. Its totient is φ = 129600.

The previous prime is 243403. The next prime is 243421. The reversal of 243405 is 504342.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 149769 + 93636 = 387^2 + 306^2 .

It is not a de Polignac number, because 243405 - 2¹ = 243403 is a prime.

It is an Ulam number.

It is a congruent number.

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

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 105 + ... + 705.

2²⁴³⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

243405 is a deficient number, since it is larger than the sum of its proper divisors (193647).

243405 is an equidigital number, since it uses as much as digits as its factorization.

243405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618 (or 609 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 18.

The square root of 243405 is about 493.3609226520. The cubic root of 243405 is about 62.4371635131.

Adding to 243405 its reverse (504342), we get a palindrome (747747).

The spelling of 243405 in words is "two hundred forty-three thousand, four hundred five".