243865541 has 2 divisors, whose sum is σ = 243865542. Its totient is φ = 243865540.

The previous prime is 243865529. The next prime is 243865543. The reversal of 243865541 is 145568342.

243865541 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137569441 + 106296100 = 11729^2 + 10310^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243865541 is a prime.

Together with 243865543, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 243865495 and 243865504.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243865543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121932770 + 121932771.

It is an arithmetic number, because the mean of its divisors is an integer number (121932771).

Almost surely, 2^243865541 is an apocalyptic number.

It is an amenable number.

243865541 is a deficient number, since it is larger than the sum of its proper divisors (1).

243865541 is an equidigital number, since it uses as much as digits as its factorization.

243865541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 115200, while the sum is 38.

The square root of 243865541 is about 15616.1948310080. The cubic root of 243865541 is about 624.7651734348.

The spelling of 243865541 in words is "two hundred forty-three million, eight hundred sixty-five thousand, five hundred forty-one".