243640403 has 4 divisors (see below), whose sum is σ = 254233488. Its totient is φ = 233047320.

The previous prime is 243640399. The next prime is 243640427. The reversal of 243640403 is 304046342.

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

It is a cyclic number.

It is not a de Polignac number, because 243640403 - 2² = 243640399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243642403) 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 3 ways as a sum of consecutive naturals, for example, 5296508 + ... + 5296553.

It is an arithmetic number, because the mean of its divisors is an integer number (63558372).

Almost surely, 2^243640403 is an apocalyptic number.

243640403 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

243640403 is a deficient number, since it is larger than the sum of its proper divisors (10593085).

243640403 is a wasteful number, since it uses less digits than its factorization.

243640403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10593084.

The product of its (nonzero) digits is 6912, while the sum is 26.

The square root of 243640403 is about 15608.9846883133. The cubic root of 243640403 is about 624.5728520312.

Adding to 243640403 its reverse (304046342), we get a palindrome (547686745).

The spelling of 243640403 in words is "two hundred forty-three million, six hundred forty thousand, four hundred three".