6678409 has 4 divisors (see below), whose sum is σ = 6683716. Its totient is φ = 6673104.

The previous prime is 6678401. The next prime is 6678421. The reversal of 6678409 is 9048766.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 5569600 + 1108809 = 2360^2 + 1053^2 .

It is a cyclic number.

It is not a de Polignac number, because 6678409 - 2³ = 6678401 is a prime.

It is a super-2 number, since 2×6678409² = 89202293542562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6678401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 427 + ... + 3679.

It is an arithmetic number, because the mean of its divisors is an integer number (1670929).

Almost surely, 2^6678409 is an apocalyptic number.

It is an amenable number.

6678409 is a deficient number, since it is larger than the sum of its proper divisors (5307).

6678409 is a wasteful number, since it uses less digits than its factorization.

6678409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5306.

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 6678409 is about 2584.2617901443. The cubic root of 6678409 is about 188.3176405508.

The spelling of 6678409 in words is "six million, six hundred seventy-eight thousand, four hundred nine".