243121421503 has 4 divisors (see below), whose sum is σ = 243247327848. Its totient is φ = 242995515160.

The previous prime is 243121421471. The next prime is 243121421509. The reversal of 243121421503 is 305124121342.

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

It is a cyclic number.

It is not a de Polignac number, because 243121421503 - 2⁵ = 243121421471 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 (243121421509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62950276 + ... + 62954137.

It is an arithmetic number, because the mean of its divisors is an integer number (60811831962).

Almost surely, 2^243121421503 is an apocalyptic number.

243121421503 is a deficient number, since it is larger than the sum of its proper divisors (125906345).

243121421503 is a wasteful number, since it uses less digits than its factorization.

243121421503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125906344.

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

Adding to 243121421503 its reverse (305124121342), we get a palindrome (548245542845).

The spelling of 243121421503 in words is "two hundred forty-three billion, one hundred twenty-one million, four hundred twenty-one thousand, five hundred three".