6686561 has 4 divisors (see below), whose sum is σ = 7641792. Its totient is φ = 5731332.

The previous prime is 6686539. The next prime is 6686569. The reversal of 6686561 is 1656866.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6686561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6686569) 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, 477605 + ... + 477618.

It is an arithmetic number, because the mean of its divisors is an integer number (1910448).

Almost surely, 2^6686561 is an apocalyptic number.

It is an amenable number.

6686561 is a deficient number, since it is larger than the sum of its proper divisors (955231).

6686561 is an equidigital number, since it uses as much as digits as its factorization.

6686561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 955230.

The product of its digits is 51840, while the sum is 38.

The square root of 6686561 is about 2585.8385487110. The cubic root of 6686561 is about 188.3942327050.

The spelling of 6686561 in words is "six million, six hundred eighty-six thousand, five hundred sixty-one".