243390857 has 2 divisors, whose sum is σ = 243390858. Its totient is φ = 243390856.

The previous prime is 243390841. The next prime is 243390859. The reversal of 243390857 is 758093342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 230402041 + 12988816 = 15179^2 + 3604^2 .

It is a cyclic number.

It is not a de Polignac number, because 243390857 - 2⁴ = 243390841 is a prime.

Together with 243390859, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (243390859) 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 as a sum of consecutive naturals, namely, 121695428 + 121695429.

It is an arithmetic number, because the mean of its divisors is an integer number (121695429).

Almost surely, 2^243390857 is an apocalyptic number.

It is an amenable number.

243390857 is a deficient number, since it is larger than the sum of its proper divisors (1).

243390857 is an equidigital number, since it uses as much as digits as its factorization.

243390857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 181440, while the sum is 41.

The square root of 243390857 is about 15600.9889750618. The cubic root of 243390857 is about 624.3595418990.

The spelling of 243390857 in words is "two hundred forty-three million, three hundred ninety thousand, eight hundred fifty-seven".