243216257 has 2 divisors, whose sum is σ = 243216258. Its totient is φ = 243216256.

The previous prime is 243216241. The next prime is 243216271. The reversal of 243216257 is 752612342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 148815601 + 94400656 = 12199^2 + 9716^2 .

It is a cyclic number.

It is not a de Polignac number, because 243216257 - 2⁴ = 243216241 is a prime.

It is not a weakly prime, because it can be changed into another prime (243216227) 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, 121608128 + 121608129.

It is an arithmetic number, because the mean of its divisors is an integer number (121608129).

Almost surely, 2^243216257 is an apocalyptic number.

It is an amenable number.

243216257 is a deficient number, since it is larger than the sum of its proper divisors (1).

243216257 is an equidigital number, since it uses as much as digits as its factorization.

243216257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 32.

The square root of 243216257 is about 15595.3921720488. The cubic root of 243216257 is about 624.2102083604.

Adding to 243216257 its reverse (752612342), we get a palindrome (995828599).

The spelling of 243216257 in words is "two hundred forty-three million, two hundred sixteen thousand, two hundred fifty-seven".