243121223305 has 4 divisors (see below), whose sum is σ = 291745467972. Its totient is φ = 194496978640.

The previous prime is 243121223299. The next prime is 243121223309. The reversal of 243121223305 is 503322121342.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 503322121342 = 2 ⋅251661060671.

It can be written as a sum of positive squares in 2 ways, for example, as 63941719689 + 179179503616 = 252867^2 + 423296^2 .

It is not a de Polignac number, because 243121223305 - 2⁹ = 243121222793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243121223309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24312122326 + ... + 24312122335.

It is an arithmetic number, because the mean of its divisors is an integer number (72936366993).

Almost surely, 2^243121223305 is an apocalyptic number.

It is an amenable number.

243121223305 is a deficient number, since it is larger than the sum of its proper divisors (48624244667).

243121223305 is an equidigital number, since it uses as much as digits as its factorization.

243121223305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48624244666.

The product of its (nonzero) digits is 8640, while the sum is 28.

Adding to 243121223305 its reverse (503322121342), we get a palindrome (746443344647).

The spelling of 243121223305 in words is "two hundred forty-three billion, one hundred twenty-one million, two hundred twenty-three thousand, three hundred five".