243330991 has 2 divisors, whose sum is σ = 243330992. Its totient is φ = 243330990.

The previous prime is 243330977. The next prime is 243331087. The reversal of 243330991 is 199033342.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 243330991 - 2¹³ = 243322799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243330931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121665495 + 121665496.

It is an arithmetic number, because the mean of its divisors is an integer number (121665496).

Almost surely, 2^243330991 is an apocalyptic number.

243330991 is a deficient number, since it is larger than the sum of its proper divisors (1).

243330991 is an equidigital number, since it uses as much as digits as its factorization.

243330991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 34.

The square root of 243330991 is about 15599.0701966495. The cubic root of 243330991 is about 624.3083471886.

The spelling of 243330991 in words is "two hundred forty-three million, three hundred thirty thousand, nine hundred ninety-one".