243121240221 has 4 divisors (see below), whose sum is σ = 324161653632. Its totient is φ = 162080826812.

The previous prime is 243121240207. The next prime is 243121240223. The reversal of 243121240221 is 122042121342.

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 not a de Polignac number, because 243121240221 - 2⁷ = 243121240093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 243121240191 and 243121240200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243121240223) 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, 40520206701 + ... + 40520206706.

It is an arithmetic number, because the mean of its divisors is an integer number (81040413408).

Almost surely, 2^243121240221 is an apocalyptic number.

It is an amenable number.

243121240221 is a deficient number, since it is larger than the sum of its proper divisors (81040413411).

243121240221 is an equidigital number, since it uses as much as digits as its factorization.

243121240221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81040413410.

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 243121240221 its reverse (122042121342), we get a palindrome (365163361563).

The spelling of 243121240221 in words is "two hundred forty-three billion, one hundred twenty-one million, two hundred forty thousand, two hundred twenty-one".