243421543 has 2 divisors, whose sum is σ = 243421544. Its totient is φ = 243421542.

The previous prime is 243421531. The next prime is 243421609. The reversal of 243421543 is 345124342.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 243421543 - 2⁵ = 243421511 is a prime.

It is equal to p_13338730 and since 243421543 and 13338730 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243421043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121710771 + 121710772.

It is an arithmetic number, because the mean of its divisors is an integer number (121710772).

Almost surely, 2^243421543 is an apocalyptic number.

243421543 is a deficient number, since it is larger than the sum of its proper divisors (1).

243421543 is an equidigital number, since it uses as much as digits as its factorization.

243421543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 28.

The square root of 243421543 is about 15601.9724073593. The cubic root of 243421543 is about 624.3857799317.

Adding to 243421543 its reverse (345124342), we get a palindrome (588545885).

The spelling of 243421543 in words is "two hundred forty-three million, four hundred twenty-one thousand, five hundred forty-three".