243061909 has 4 divisors (see below), whose sum is σ = 243927180. Its totient is φ = 242196640.

The previous prime is 243061891. The next prime is 243061913. The reversal of 243061909 is 909160342.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 909160342 = 2 ⋅454580171.

It can be written as a sum of positive squares in 2 ways, for example, as 132181009 + 110880900 = 11497^2 + 10530^2 .

It is a cyclic number.

It is not a de Polignac number, because 243061909 - 2⁵ = 243061877 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 (243061939) 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, 432214 + ... + 432775.

It is an arithmetic number, because the mean of its divisors is an integer number (60981795).

Almost surely, 2^243061909 is an apocalyptic number.

It is an amenable number.

243061909 is a deficient number, since it is larger than the sum of its proper divisors (865271).

243061909 is an equidigital number, since it uses as much as digits as its factorization.

243061909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 865270.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 243061909 is about 15590.4428737608. The cubic root of 243061909 is about 624.0781366172.

The spelling of 243061909 in words is "two hundred forty-three million, sixty-one thousand, nine hundred nine".