6409 has 8 divisors (see below), whose sum is σ = 7560. Its totient is φ = 5376.

The previous prime is 6397. The next prime is 6421. The reversal of 6409 is 9046.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (6397) and next prime (6421).

It can be written as a sum of positive squares in 4 ways, for example, as 784 + 5625 = 28^2 + 75^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6409 - 2⁹ = 5897 is a prime.

It is a house number.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a nialpdrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 207 + ... + 235.

It is an arithmetic number, because the mean of its divisors is an integer number (945).

It is an amenable number.

6409 is a deficient number, since it is larger than the sum of its proper divisors (1151).

6409 is a wasteful number, since it uses less digits than its factorization.

6409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 6409 is about 80.0562302385. The cubic root of 6409 is about 18.5750542372.

Multiplying 6409 by its sum of digits (19), we get a triangular number (121771 = T₄₉₃).

The spelling of 6409 in words is "six thousand, four hundred nine".