6686591 has 2 divisors, whose sum is σ = 6686592. Its totient is φ = 6686590.

The previous prime is 6686569. The next prime is 6686611. The reversal of 6686591 is 1956866.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6686591 - 2⁶ = 6686527 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6686191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3343295 + 3343296.

It is an arithmetic number, because the mean of its divisors is an integer number (3343296).

Almost surely, 2^6686591 is an apocalyptic number.

6686591 is a deficient number, since it is larger than the sum of its proper divisors (1).

6686591 is an equidigital number, since it uses as much as digits as its factorization.

6686591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 41.

The square root of 6686591 is about 2585.8443495307. The cubic root of 6686591 is about 188.3945144551.

The spelling of 6686591 in words is "six million, six hundred eighty-six thousand, five hundred ninety-one".