243121204505 has 16 divisors (see below), whose sum is σ = 299676959184. Its totient is φ = 189210919680.

The previous prime is 243121204477. The next prime is 243121204583. The reversal of 243121204505 is 505402121342.

243121204505 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 22085823769 + 221035380736 = 148613^2 + 470144^2 .

It is a de Polignac number, because none of the positive numbers 2^k-243121204505 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1133639 + ... + 1330931.

It is an arithmetic number, because the mean of its divisors is an integer number (18729809949).

Almost surely, 2^243121204505 is an apocalyptic number.

It is an amenable number.

243121204505 is a deficient number, since it is larger than the sum of its proper divisors (56555754679).

243121204505 is a wasteful number, since it uses less digits than its factorization.

243121204505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203996.

The product of its (nonzero) digits is 9600, while the sum is 29.

Adding to 243121204505 its reverse (505402121342), we get a palindrome (748523325847).

The spelling of 243121204505 in words is "two hundred forty-three billion, one hundred twenty-one million, two hundred four thousand, five hundred five".