243123091 has 2 divisors, whose sum is σ = 243123092. Its totient is φ = 243123090.

The previous prime is 243123079. The next prime is 243123113. The reversal of 243123091 is 190321342.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 243123091 - 2¹⁹ = 242598803 is a prime.

It is not a weakly prime, because it can be changed into another prime (243123061) 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, 121561545 + 121561546.

It is an arithmetic number, because the mean of its divisors is an integer number (121561546).

Almost surely, 2^243123091 is an apocalyptic number.

243123091 is a deficient number, since it is larger than the sum of its proper divisors (1).

243123091 is an equidigital number, since it uses as much as digits as its factorization.

243123091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 243123091 is about 15592.4049139317. The cubic root of 243123091 is about 624.1304952193.

The spelling of 243123091 in words is "two hundred forty-three million, one hundred twenty-three thousand, ninety-one".