243500621657 has 2 divisors, whose sum is σ = 243500621658. Its totient is φ = 243500621656.

The previous prime is 243500621599. The next prime is 243500621681. The reversal of 243500621657 is 756126005342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 241209659161 + 2290962496 = 491131^2 + 47864^2 .

It is a cyclic number.

It is not a de Polignac number, because 243500621657 - 2⁶ = 243500621593 is a prime.

It is not a weakly prime, because it can be changed into another prime (243500621257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121750310828 + 121750310829.

It is an arithmetic number, because the mean of its divisors is an integer number (121750310829).

Almost surely, 2^243500621657 is an apocalyptic number.

It is an amenable number.

243500621657 is a deficient number, since it is larger than the sum of its proper divisors (1).

243500621657 is an equidigital number, since it uses as much as digits as its factorization.

243500621657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 302400, while the sum is 41.

Adding to 243500621657 its reverse (756126005342), we get a palindrome (999626626999).

The spelling of 243500621657 in words is "two hundred forty-three billion, five hundred million, six hundred twenty-one thousand, six hundred fifty-seven".