43209 has 6 divisors (see below), whose sum is σ = 62426. Its totient is φ = 28800.

The previous prime is 43207. The next prime is 43223. The reversal of 43209 is 90234.

It can be written as a sum of positive squares in only one way, i.e., 38025 + 5184 = 195^2 + 72^2 .

It is not a de Polignac number, because 43209 - 2¹ = 43207 is a prime.

It is a Duffinian number.

43209 is a lucky number.

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 43191 and 43200.

It is not an unprimeable number, because it can be changed into a prime (43201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2392 + ... + 2409.

2⁴³²⁰⁹ is an apocalyptic number.

It is an amenable number.

43209 is a deficient number, since it is larger than the sum of its proper divisors (19217).

43209 is a wasteful number, since it uses less digits than its factorization.

43209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4807 (or 4804 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 43209 is about 207.8677464158. The cubic root of 43209 is about 35.0906493708.

It can be divided in two parts, 43 and 209, that added together give a palindrome (252).

The spelling of 43209 in words is "forty-three thousand, two hundred nine".