243111221 has 4 divisors (see below), whose sum is σ = 243262272. Its totient is φ = 242960172.

The previous prime is 243111217. The next prime is 243111223. The reversal of 243111221 is 122111342.

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, and also an emirpimes, since its reverse is a distinct semiprime: 122111342 = 2 ⋅61055671.

It is a cyclic number.

It is not a de Polignac number, because 243111221 - 2² = 243111217 is a prime.

It is a super-2 number, since 2×243111221² = 118206131552221682, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 243111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243111223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73085 + ... + 76338.

It is an arithmetic number, because the mean of its divisors is an integer number (60815568).

Almost surely, 2^243111221 is an apocalyptic number.

It is an amenable number.

243111221 is a deficient number, since it is larger than the sum of its proper divisors (151051).

243111221 is a wasteful number, since it uses less digits than its factorization.

243111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151050.

The product of its digits is 96, while the sum is 17.

The square root of 243111221 is about 15592.0242752505. The cubic root of 243111221 is about 624.1203377451.

Adding to 243111221 its reverse (122111342), we get a palindrome (365222563).

The spelling of 243111221 in words is "two hundred forty-three million, one hundred eleven thousand, two hundred twenty-one".