43209421 has 2 divisors, whose sum is σ = 43209422. Its totient is φ = 43209420.

The previous prime is 43209379. The next prime is 43209431. The reversal of 43209421 is 12490234.

43209421 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., 43164900 + 44521 = 6570^2 + 211^2 .

It is a cyclic number.

It is not a de Polignac number, because 43209421 - 2⁷ = 43209293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43209431) 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, 21604710 + 21604711.

It is an arithmetic number, because the mean of its divisors is an integer number (21604711).

Almost surely, 2^43209421 is an apocalyptic number.

It is an amenable number.

43209421 is a deficient number, since it is larger than the sum of its proper divisors (1).

43209421 is an equidigital number, since it uses as much as digits as its factorization.

43209421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 43209421 is about 6573.3873307451. The cubic root of 43209421 is about 350.9076333715.

Adding to 43209421 its reverse (12490234), we get a palindrome (55699655).

The spelling of 43209421 in words is "forty-three million, two hundred nine thousand, four hundred twenty-one".