243504809 has 2 divisors, whose sum is σ = 243504810. Its totient is φ = 243504808.

The previous prime is 243504797. The next prime is 243504853. The reversal of 243504809 is 908405342.

243504809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 241709209 + 1795600 = 15547^2 + 1340^2 .

It is a cyclic number.

It is not a de Polignac number, because 243504809 - 2⁸ = 243504553 is a prime.

It is a super-2 number, since 2×243504809² = 118589184012252962, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (243504869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121752404 + 121752405.

It is an arithmetic number, because the mean of its divisors is an integer number (121752405).

Almost surely, 2^243504809 is an apocalyptic number.

It is an amenable number.

243504809 is a deficient number, since it is larger than the sum of its proper divisors (1).

243504809 is an equidigital number, since it uses as much as digits as its factorization.

243504809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 243504809 is about 15604.6406238657. The cubic root of 243504809 is about 624.4569653313.

The spelling of 243504809 in words is "two hundred forty-three million, five hundred four thousand, eight hundred nine".