243131521057 has 2 divisors, whose sum is σ = 243131521058. Its totient is φ = 243131521056.

The previous prime is 243131521051. The next prime is 243131521081. The reversal of 243131521057 is 750125131342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 130004234721 + 113127286336 = 360561^2 + 336344^2 .

It is a cyclic number.

It is not a de Polignac number, because 243131521057 - 2²³ = 243123132449 is a prime.

It is a super-2 number, since 2×243131521057² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (243131521051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121565760528 + 121565760529.

It is an arithmetic number, because the mean of its divisors is an integer number (121565760529).

Almost surely, 2^243131521057 is an apocalyptic number.

It is an amenable number.

243131521057 is a deficient number, since it is larger than the sum of its proper divisors (1).

243131521057 is an equidigital number, since it uses as much as digits as its factorization.

243131521057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25200, while the sum is 34.

Adding to 243131521057 its reverse (750125131342), we get a palindrome (993256652399).

The spelling of 243131521057 in words is "two hundred forty-three billion, one hundred thirty-one million, five hundred twenty-one thousand, fifty-seven".