6687691 has 4 divisors (see below), whose sum is σ = 6699672. Its totient is φ = 6675712.

The previous prime is 6687689. The next prime is 6687701. The reversal of 6687691 is 1967866.

6687691 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 6687691 - 2¹ = 6687689 is a prime.

It is a super-2 number, since 2×6687691² = 89450421822962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6687631) 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, 5110 + ... + 6283.

It is an arithmetic number, because the mean of its divisors is an integer number (1674918).

Almost surely, 2^6687691 is an apocalyptic number.

6687691 is a deficient number, since it is larger than the sum of its proper divisors (11981).

6687691 is a wasteful number, since it uses less digits than its factorization.

6687691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11980.

The product of its digits is 108864, while the sum is 43.

The square root of 6687691 is about 2586.0570372674. The cubic root of 6687691 is about 188.4048447117.

The spelling of 6687691 in words is "six million, six hundred eighty-seven thousand, six hundred ninety-one".