243121244557 has 2 divisors, whose sum is σ = 243121244558. Its totient is φ = 243121244556.

The previous prime is 243121244417. The next prime is 243121244617. The reversal of 243121244557 is 755442121342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 237938108521 + 5183136036 = 487789^2 + 71994^2 .

It is a cyclic number.

It is not a de Polignac number, because 243121244557 - 2¹⁵ = 243121211789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243121244857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121560622278 + 121560622279.

It is an arithmetic number, because the mean of its divisors is an integer number (121560622279).

Almost surely, 2^243121244557 is an apocalyptic number.

It is an amenable number.

243121244557 is a deficient number, since it is larger than the sum of its proper divisors (1).

243121244557 is an equidigital number, since it uses as much as digits as its factorization.

243121244557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 268800, while the sum is 40.

Adding to 243121244557 its reverse (755442121342), we get a palindrome (998563365899).

The spelling of 243121244557 in words is "two hundred forty-three billion, one hundred twenty-one million, two hundred forty-four thousand, five hundred fifty-seven".