243538993 has 4 divisors (see below), whose sum is σ = 244612080. Its totient is φ = 242465908.

The previous prime is 243538951. The next prime is 243539003. The reversal of 243538993 is 399835342.

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.

It is a cyclic number.

It is not a de Polignac number, because 243538993 - 2²¹ = 241441841 is a prime.

It is a super-3 number, since 3×243538993³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243538693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 536203 + ... + 536656.

It is an arithmetic number, because the mean of its divisors is an integer number (61153020).

Almost surely, 2^243538993 is an apocalyptic number.

It is an amenable number.

243538993 is a deficient number, since it is larger than the sum of its proper divisors (1073087).

243538993 is a wasteful number, since it uses less digits than its factorization.

243538993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073086.

The product of its digits is 699840, while the sum is 46.

The square root of 243538993 is about 15605.7359006232. The cubic root of 243538993 is about 624.4861850665.

The spelling of 243538993 in words is "two hundred forty-three million, five hundred thirty-eight thousand, nine hundred ninety-three".