243243123421 has 4 divisors (see below), whose sum is σ = 243333990172. Its totient is φ = 243152256672.

The previous prime is 243243123311. The next prime is 243243123443. The reversal of 243243123421 is 124321342342.

243243123421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 52963959321 + 190279164100 = 230139^2 + 436210^2 .

It is a cyclic number.

It is not a de Polignac number, because 243243123421 - 2¹⁵ = 243243090653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243243103421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45429360 + ... + 45434713.

It is an arithmetic number, because the mean of its divisors is an integer number (60833497543).

Almost surely, 2^243243123421 is an apocalyptic number.

It is an amenable number.

243243123421 is a deficient number, since it is larger than the sum of its proper divisors (90866751).

243243123421 is an equidigital number, since it uses as much as digits as its factorization.

243243123421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90866750.

The product of its digits is 27648, while the sum is 31.

Adding to 243243123421 its reverse (124321342342), we get a palindrome (367564465763).

The spelling of 243243123421 in words is "two hundred forty-three billion, two hundred forty-three million, one hundred twenty-three thousand, four hundred twenty-one".