6688987 has 4 divisors (see below), whose sum is σ = 6722800. Its totient is φ = 6655176.

The previous prime is 6688967. The next prime is 6688999. The reversal of 6688987 is 7898866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7898866 = 2 ⋅3949433.

It is a cyclic number.

It is not a de Polignac number, because 6688987 - 2⁷ = 6688859 is a prime.

It is a Duffinian number.

6688987 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6688907) 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, 16608 + ... + 17005.

It is an arithmetic number, because the mean of its divisors is an integer number (1680700).

Almost surely, 2^6688987 is an apocalyptic number.

6688987 is a deficient number, since it is larger than the sum of its proper divisors (33813).

6688987 is a wasteful number, since it uses less digits than its factorization.

6688987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33812.

The product of its digits is 1161216, while the sum is 52.

The square root of 6688987 is about 2586.3075996486. The cubic root of 6688987 is about 188.4170141789.

The spelling of 6688987 in words is "six million, six hundred eighty-eight thousand, nine hundred eighty-seven".