243004561 has 2 divisors, whose sum is σ = 243004562. Its totient is φ = 243004560.

The previous prime is 243004507. The next prime is 243004589. The reversal of 243004561 is 165400342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172108161 + 70896400 = 13119^2 + 8420^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243004561 is a prime.

It is not a weakly prime, because it can be changed into another prime (243002561) 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, 121502280 + 121502281.

It is an arithmetic number, because the mean of its divisors is an integer number (121502281).

Almost surely, 2^243004561 is an apocalyptic number.

It is an amenable number.

243004561 is a deficient number, since it is larger than the sum of its proper divisors (1).

243004561 is an equidigital number, since it uses as much as digits as its factorization.

243004561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 243004561 is about 15588.6035615766. The cubic root of 243004561 is about 624.0290511143.

The spelling of 243004561 in words is "two hundred forty-three million, four thousand, five hundred sixty-one".