243121021513 has 2 divisors, whose sum is σ = 243121021514. Its totient is φ = 243121021512.

The previous prime is 243121021489. The next prime is 243121021543. The reversal of 243121021513 is 315120121342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135223881984 + 107897139529 = 367728^2 + 328477^2 .

It is a cyclic number.

It is not a de Polignac number, because 243121021513 - 2⁹ = 243121021001 is a prime.

It is a super-2 number, since 2×243121021513² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (243121021543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121560510756 + 121560510757.

It is an arithmetic number, because the mean of its divisors is an integer number (121560510757).

Almost surely, 2^243121021513 is an apocalyptic number.

It is an amenable number.

243121021513 is a deficient number, since it is larger than the sum of its proper divisors (1).

243121021513 is an equidigital number, since it uses as much as digits as its factorization.

243121021513 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 25.

Adding to 243121021513 its reverse (315120121342), we get a palindrome (558241142855).

The spelling of 243121021513 in words is "two hundred forty-three billion, one hundred twenty-one million, twenty-one thousand, five hundred thirteen".