6681987 has 16 divisors (see below), whose sum is σ = 10661280. Its totient is φ = 4111776.

The previous prime is 6681979. The next prime is 6681989. The reversal of 6681987 is 7891866.

It is a happy number.

It is not a de Polignac number, because 6681987 - 2³ = 6681979 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6681989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9168 + ... + 9869.

It is an arithmetic number, because the mean of its divisors is an integer number (666330).

Almost surely, 2^6681987 is an apocalyptic number.

6681987 is a deficient number, since it is larger than the sum of its proper divisors (3979293).

6681987 is a wasteful number, since it uses less digits than its factorization.

6681987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19059 (or 19053 counting only the distinct ones).

The product of its digits is 145152, while the sum is 45.

The square root of 6681987 is about 2584.9539647738. The cubic root of 6681987 is about 188.3512653369.

The spelling of 6681987 in words is "six million, six hundred eighty-one thousand, nine hundred eighty-seven".