43664809 has 2 divisors, whose sum is σ = 43664810. Its totient is φ = 43664808.

The previous prime is 43664791. The next prime is 43664813. The reversal of 43664809 is 90846634.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43520409 + 144400 = 6597^2 + 380^2 .

It is a cyclic number.

It is not a de Polignac number, because 43664809 - 2⁹ = 43664297 is a prime.

It is not a weakly prime, because it can be changed into another prime (43664849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21832404 + 21832405.

It is an arithmetic number, because the mean of its divisors is an integer number (21832405).

Almost surely, 2^43664809 is an apocalyptic number.

It is an amenable number.

43664809 is a deficient number, since it is larger than the sum of its proper divisors (1).

43664809 is an equidigital number, since it uses as much as digits as its factorization.

43664809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 40.

The square root of 43664809 is about 6607.9353053734. The cubic root of 43664809 is about 352.1360769725.

The spelling of 43664809 in words is "forty-three million, six hundred sixty-four thousand, eight hundred nine".