243421 has 2 divisors, whose sum is σ = 243422. Its totient is φ = 243420.

The previous prime is 243403. The next prime is 243431. The reversal of 243421 is 124342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 236196 + 7225 = 486^2 + 85^2 .

It is a cyclic number.

It is not a de Polignac number, because 243421 - 2¹⁷ = 112349 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 243395 and 243404.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243401) by changing a digit.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121710 + 121711.

It is an arithmetic number, because the mean of its divisors is an integer number (121711).

2²⁴³⁴²¹ is an apocalyptic number.

It is an amenable number.

243421 is a deficient number, since it is larger than the sum of its proper divisors (1).

243421 is an equidigital number, since it uses as much as digits as its factorization.

243421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 192, while the sum is 16.

The square root of 243421 is about 493.3771376949. The cubic root of 243421 is about 62.4385315659.

Adding to 243421 its reverse (124342), we get a palindrome (367763).

The spelling of 243421 in words is "two hundred forty-three thousand, four hundred twenty-one", and thus it is an iban number.