243646621 has 2 divisors, whose sum is σ = 243646622. Its totient is φ = 243646620.

The previous prime is 243646609. The next prime is 243646631. The reversal of 243646621 is 126646342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 235008900 + 8637721 = 15330^2 + 2939^2 .

It is a cyclic number.

It is not a de Polignac number, because 243646621 - 2⁵ = 243646589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243646631) 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, 121823310 + 121823311.

It is an arithmetic number, because the mean of its divisors is an integer number (121823311).

Almost surely, 2^243646621 is an apocalyptic number.

It is an amenable number.

243646621 is a deficient number, since it is larger than the sum of its proper divisors (1).

243646621 is an equidigital number, since it uses as much as digits as its factorization.

243646621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41472, while the sum is 34.

The square root of 243646621 is about 15609.1838671982. The cubic root of 243646621 is about 624.5781652728.

The spelling of 243646621 in words is "two hundred forty-three million, six hundred forty-six thousand, six hundred twenty-one".