243121043021 has 4 divisors (see below), whose sum is σ = 250963657344. Its totient is φ = 235278428700.

The previous prime is 243121042993. The next prime is 243121043029. The reversal of 243121043021 is 120340121342.

243121043021 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243121043021 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 (243121043029) 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, 3921307115 + ... + 3921307176.

It is an arithmetic number, because the mean of its divisors is an integer number (62740914336).

Almost surely, 2^243121043021 is an apocalyptic number.

It is an amenable number.

243121043021 is a deficient number, since it is larger than the sum of its proper divisors (7842614323).

243121043021 is an equidigital number, since it uses as much as digits as its factorization.

243121043021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7842614322.

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 243121043021 its reverse (120340121342), we get a palindrome (363461164363).

The spelling of 243121043021 in words is "two hundred forty-three billion, one hundred twenty-one million, forty-three thousand, twenty-one".