243203351557 has 2 divisors, whose sum is σ = 243203351558. Its totient is φ = 243203351556.

The previous prime is 243203351491. The next prime is 243203351561. The reversal of 243203351557 is 755153302342.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 203914561761 + 39288789796 = 451569^2 + 198214^2 .

It is a cyclic number.

It is not a de Polignac number, because 243203351557 - 2¹⁹ = 243202827269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243203351597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121601675778 + 121601675779.

It is an arithmetic number, because the mean of its divisors is an integer number (121601675779).

Almost surely, 2^243203351557 is an apocalyptic number.

It is an amenable number.

243203351557 is a deficient number, since it is larger than the sum of its proper divisors (1).

243203351557 is an equidigital number, since it uses as much as digits as its factorization.

243203351557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 378000, while the sum is 40.

Adding to 243203351557 its reverse (755153302342), we get a palindrome (998356653899).

The spelling of 243203351557 in words is "two hundred forty-three billion, two hundred three million, three hundred fifty-one thousand, five hundred fifty-seven".