243437521 has 2 divisors, whose sum is σ = 243437522. Its totient is φ = 243437520.

The previous prime is 243437507. The next prime is 243437531. The reversal of 243437521 is 125734342.

It is a happy number.

243437521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 143137296 + 100300225 = 11964^2 + 10015^2 .

It is a cyclic number.

It is not a de Polignac number, because 243437521 - 2⁵ = 243437489 is a prime.

It is not a weakly prime, because it can be changed into another prime (243437531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121718760 + 121718761.

It is an arithmetic number, because the mean of its divisors is an integer number (121718761).

Almost surely, 2^243437521 is an apocalyptic number.

It is an amenable number.

243437521 is a deficient number, since it is larger than the sum of its proper divisors (1).

243437521 is an equidigital number, since it uses as much as digits as its factorization.

243437521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 31.

The square root of 243437521 is about 15602.4844495997. The cubic root of 243437521 is about 624.3994410311.

The spelling of 243437521 in words is "two hundred forty-three million, four hundred thirty-seven thousand, five hundred twenty-one".