6686491 has 24 divisors (see below), whose sum is σ = 8618400. Its totient is φ = 5144832.

The previous prime is 6686489. The next prime is 6686507. The reversal of 6686491 is 1946866.

It is not a de Polignac number, because 6686491 - 2¹ = 6686489 is a prime.

6686491 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6686191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18985 + ... + 19333.

It is an arithmetic number, because the mean of its divisors is an integer number (359100).

Almost surely, 2^6686491 is an apocalyptic number.

6686491 is a deficient number, since it is larger than the sum of its proper divisors (1931909).

6686491 is a wasteful number, since it uses less digits than its factorization.

6686491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403 (or 396 counting only the distinct ones).

The product of its digits is 62208, while the sum is 40.

The square root of 6686491 is about 2585.8250134145. The cubic root of 6686491 is about 188.3935752847.

The spelling of 6686491 in words is "six million, six hundred eighty-six thousand, four hundred ninety-one".