43644666809 has 2 divisors, whose sum is σ = 43644666810. Its totient is φ = 43644666808.

The previous prime is 43644666799. The next prime is 43644666811. The reversal of 43644666809 is 90866644634.

43644666809 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., 41637626809 + 2007040000 = 204053^2 + 44800^2 .

It is a cyclic number.

It is not a de Polignac number, because 43644666809 - 2⁸ = 43644666553 is a prime.

It is a Sophie Germain prime.

Together with 43644666811, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (43644606809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21822333404 + 21822333405.

It is an arithmetic number, because the mean of its divisors is an integer number (21822333405).

Almost surely, 2^43644666809 is an apocalyptic number.

It is an amenable number.

43644666809 is a deficient number, since it is larger than the sum of its proper divisors (1).

43644666809 is an equidigital number, since it uses as much as digits as its factorization.

43644666809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17915904, while the sum is 56.

The spelling of 43644666809 in words is "forty-three billion, six hundred forty-four million, six hundred sixty-six thousand, eight hundred nine".