43209809 has 2 divisors, whose sum is σ = 43209810. Its totient is φ = 43209808.

The previous prime is 43209791. The next prime is 43209811. The reversal of 43209809 is 90890234.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41319184 + 1890625 = 6428^2 + 1375^2 .

It is a cyclic number.

It is not a de Polignac number, because 43209809 - 2¹² = 43205713 is a prime.

Together with 43209811, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (43200809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21604904 + 21604905.

It is an arithmetic number, because the mean of its divisors is an integer number (21604905).

Almost surely, 2^43209809 is an apocalyptic number.

It is an amenable number.

43209809 is a deficient number, since it is larger than the sum of its proper divisors (1).

43209809 is an equidigital number, since it uses as much as digits as its factorization.

43209809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 43209809 is about 6573.4168436210. The cubic root of 43209809 is about 350.9086836961.

The spelling of 43209809 in words is "forty-three million, two hundred nine thousand, eight hundred nine".