243562661 has 2 divisors, whose sum is σ = 243562662. Its totient is φ = 243562660.

The previous prime is 243562643. The next prime is 243562703. The reversal of 243562661 is 166265342.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 203632900 + 39929761 = 14270^2 + 6319^2 .

It is a cyclic number.

It is not a de Polignac number, because 243562661 - 2⁶ = 243562597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243562861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121781330 + 121781331.

It is an arithmetic number, because the mean of its divisors is an integer number (121781331).

Almost surely, 2^243562661 is an apocalyptic number.

It is an amenable number.

243562661 is a deficient number, since it is larger than the sum of its proper divisors (1).

243562661 is an equidigital number, since it uses as much as digits as its factorization.

243562661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 35.

The square root of 243562661 is about 15606.4941931236. The cubic root of 243562661 is about 624.5064143531.

The spelling of 243562661 in words is "two hundred forty-three million, five hundred sixty-two thousand, six hundred sixty-one".