243938909 has 4 divisors (see below), whose sum is σ = 246878016. Its totient is φ = 240999804.

The previous prime is 243938879. The next prime is 243938911. The reversal of 243938909 is 909839342.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 909839342 = 2 ⋅454919671.

It is a cyclic number.

It is not a de Polignac number, because 243938909 - 2¹² = 243934813 is a prime.

It is a super-2 number, since 2×243938909² = 119012382648220562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243938309) 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, 1469429 + ... + 1469594.

It is an arithmetic number, because the mean of its divisors is an integer number (61719504).

Almost surely, 2^243938909 is an apocalyptic number.

It is an amenable number.

243938909 is a deficient number, since it is larger than the sum of its proper divisors (2939107).

243938909 is an equidigital number, since it uses as much as digits as its factorization.

243938909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2939106.

The product of its (nonzero) digits is 419904, while the sum is 47.

The square root of 243938909 is about 15618.5437541405. The cubic root of 243938909 is about 624.8278215850.

The spelling of 243938909 in words is "two hundred forty-three million, nine hundred thirty-eight thousand, nine hundred nine".