243121021543 has 2 divisors, whose sum is σ = 243121021544. Its totient is φ = 243121021542.

The previous prime is 243121021513. The next prime is 243121021567. The reversal of 243121021543 is 345120121342.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 243121021543 - 2²⁹ = 242584150631 is a prime.

It is a super-2 number, since 2×243121021543² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243121021513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121560510771 + 121560510772.

It is an arithmetic number, because the mean of its divisors is an integer number (121560510772).

Almost surely, 2^243121021543 is an apocalyptic number.

243121021543 is a deficient number, since it is larger than the sum of its proper divisors (1).

243121021543 is an equidigital number, since it uses as much as digits as its factorization.

243121021543 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 28.

Adding to 243121021543 its reverse (345120121342), we get a palindrome (588241142885).

The spelling of 243121021543 in words is "two hundred forty-three billion, one hundred twenty-one million, twenty-one thousand, five hundred forty-three".