243342521 has 2 divisors, whose sum is σ = 243342522. Its totient is φ = 243342520.

The previous prime is 243342493. The next prime is 243342559. The reversal of 243342521 is 125243342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 242269225 + 1073296 = 15565^2 + 1036^2 .

It is a cyclic number.

It is not a de Polignac number, because 243342521 - 2⁶ = 243342457 is a prime.

It is not a weakly prime, because it can be changed into another prime (243332521) 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, 121671260 + 121671261.

It is an arithmetic number, because the mean of its divisors is an integer number (121671261).

Almost surely, 2^243342521 is an apocalyptic number.

It is an amenable number.

243342521 is a deficient number, since it is larger than the sum of its proper divisors (1).

243342521 is an equidigital number, since it uses as much as digits as its factorization.

243342521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5760, while the sum is 26.

The square root of 243342521 is about 15599.4397655813. The cubic root of 243342521 is about 624.3182077788.

Adding to 243342521 its reverse (125243342), we get a palindrome (368585863).

The spelling of 243342521 in words is "two hundred forty-three million, three hundred forty-two thousand, five hundred twenty-one".