8409 has 4 divisors (see below), whose sum is σ = 11216. Its totient is φ = 5604.

The previous prime is 8389. The next prime is 8419. The reversal of 8409 is 9048.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 8409 - 2⁵ = 8377 is a prime.

It is a super-2 number, since 2×8409² = 141422562, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

8409 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (8419) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1399 + ... + 1404.

It is an arithmetic number, because the mean of its divisors is an integer number (2804).

2⁸⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

8409 is a deficient number, since it is larger than the sum of its proper divisors (2807).

8409 is a wasteful number, since it uses less digits than its factorization.

8409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2806.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 8409 is about 91.7005997799. The cubic root of 8409 is about 20.3351845190.

The spelling of 8409 in words is "eight thousand, four hundred nine".