243115221257 has 2 divisors, whose sum is σ = 243115221258. Its totient is φ = 243115221256.

The previous prime is 243115221247. The next prime is 243115221329. The reversal of 243115221257 is 752122511342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 170115827401 + 72999393856 = 412451^2 + 270184^2 .

It is a cyclic number.

It is not a de Polignac number, because 243115221257 - 2¹² = 243115217161 is a prime.

It is a super-3 number, since 3×243115221257³ (a number of 35 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (243115221247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121557610628 + 121557610629.

It is an arithmetic number, because the mean of its divisors is an integer number (121557610629).

Almost surely, 2^243115221257 is an apocalyptic number.

It is an amenable number.

243115221257 is a deficient number, since it is larger than the sum of its proper divisors (1).

243115221257 is an equidigital number, since it uses as much as digits as its factorization.

243115221257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33600, while the sum is 35.

Adding to 243115221257 its reverse (752122511342), we get a palindrome (995237732599).

The spelling of 243115221257 in words is "two hundred forty-three billion, one hundred fifteen million, two hundred twenty-one thousand, two hundred fifty-seven".