43609 has 2 divisors, whose sum is σ = 43610.
Its totient is φ = 43608.
The previous prime is 43607. The next prime is 43613. The reversal of 43609 is 90634.
43609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 27225 + 16384 = 165^2 + 128^2
It is a cyclic number.
It is not a de Polignac number, because 43609 - 21 = 43607 is a prime.
Together with 43607, it forms a pair of twin primes.
It is a Chen prime.
It is a self number, because there is not a number n which added to its sum of digits gives 43609.
It is not a weakly prime, because it can be changed into another prime (43607) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21804 + 21805.
It is an arithmetic number, because the mean of its divisors is an integer number (21805).
243609 is an apocalyptic number.
It is an amenable number.
43609 is a deficient number, since it is larger than the sum of its proper divisors (1).
43609 is an equidigital number, since it uses as much as digits as its factorization.
43609 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 648, while the sum is 22.
The square root of 43609 is about 208.8276801576.
The cubic root of 43609 is about 35.1985988595.
The spelling of 43609 in words is "forty-three thousand, six hundred nine".