243342509 has 6 divisors (see below), whose sum is σ = 252023850. Its totient is φ = 234950576.

The previous prime is 243342493. The next prime is 243342521. The reversal of 243342509 is 905243342.

It can be written as a sum of positive squares in 3 ways, for example, as 63648484 + 179694025 = 7978^2 + 13405^2 .

It is not a de Polignac number, because 243342509 - 2⁴ = 243342493 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 (243342559) 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 5 ways as a sum of consecutive naturals, for example, 143834 + ... + 145515.

It is an arithmetic number, because the mean of its divisors is an integer number (42003975).

Almost surely, 2^243342509 is an apocalyptic number.

243342509 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

243342509 is a deficient number, since it is larger than the sum of its proper divisors (8681341).

243342509 is an equidigital number, since it uses as much as digits as its factorization.

243342509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289407 (or 289378 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 32.

The square root of 243342509 is about 15599.4393809521. The cubic root of 243342509 is about 624.3181975164.

The spelling of 243342509 in words is "two hundred forty-three million, three hundred forty-two thousand, five hundred nine".