6391687 has 4 divisors (see below), whose sum is σ = 6612120. Its totient is φ = 6171256.

The previous prime is 6391669. The next prime is 6391699. The reversal of 6391687 is 7861936.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6391687 - 2⁷ = 6391559 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6391607) 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 3 ways as a sum of consecutive naturals, for example, 110173 + ... + 110230.

It is an arithmetic number, because the mean of its divisors is an integer number (1653030).

Almost surely, 2^6391687 is an apocalyptic number.

6391687 is a deficient number, since it is larger than the sum of its proper divisors (220433).

6391687 is a wasteful number, since it uses less digits than its factorization.

6391687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220432.

The product of its digits is 54432, while the sum is 40.

The square root of 6391687 is about 2528.1785933751. The cubic root of 6391687 is about 185.5831319979.

The spelling of 6391687 in words is "six million, three hundred ninety-one thousand, six hundred eighty-seven".