243545221 has 2 divisors, whose sum is σ = 243545222. Its totient is φ = 243545220.

The previous prime is 243545209. The next prime is 243545227. The reversal of 243545221 is 122545342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 168636196 + 74909025 = 12986^2 + 8655^2 .

It is a cyclic number.

It is not a de Polignac number, because 243545221 - 2⁵ = 243545189 is a prime.

It is a super-3 number, since 3×243545221³ (a number of 26 digits) contains 333 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 243545221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243545227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121772610 + 121772611.

It is an arithmetic number, because the mean of its divisors is an integer number (121772611).

Almost surely, 2^243545221 is an apocalyptic number.

It is an amenable number.

243545221 is a deficient number, since it is larger than the sum of its proper divisors (1).

243545221 is an equidigital number, since it uses as much as digits as its factorization.

243545221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9600, while the sum is 28.

The square root of 243545221 is about 15605.9354413633. The cubic root of 243545221 is about 624.4915083301.

The spelling of 243545221 in words is "two hundred forty-three million, five hundred forty-five thousand, two hundred twenty-one".