243401509 has 4 divisors (see below), whose sum is σ = 262124716. Its totient is φ = 224678304.

The previous prime is 243401507. The next prime is 243401513. The reversal of 243401509 is 905104342.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10381284 + 233020225 = 3222^2 + 15265^2 .

It is a cyclic number.

It is not a de Polignac number, because 243401509 - 2¹ = 243401507 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 (243401507) 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, 9361584 + ... + 9361609.

It is an arithmetic number, because the mean of its divisors is an integer number (65531179).

Almost surely, 2^243401509 is an apocalyptic number.

It is an amenable number.

243401509 is a deficient number, since it is larger than the sum of its proper divisors (18723207).

243401509 is a wasteful number, since it uses less digits than its factorization.

243401509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18723206.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 243401509 is about 15601.3303599405. The cubic root of 243401509 is about 624.3686501305.

The spelling of 243401509 in words is "two hundred forty-three million, four hundred one thousand, five hundred nine".