6681891 has 16 divisors (see below), whose sum is σ = 9365760. Its totient is φ = 4229280.

The previous prime is 6681889. The next prime is 6681923. The reversal of 6681891 is 1981866.

It is not a de Polignac number, because 6681891 - 2¹ = 6681889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6681491) 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, 12081 + ... + 12621.

It is an arithmetic number, because the mean of its divisors is an integer number (585360).

Almost surely, 2^6681891 is an apocalyptic number.

6681891 is a deficient number, since it is larger than the sum of its proper divisors (2683869).

6681891 is a wasteful number, since it uses less digits than its factorization.

6681891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 746.

The product of its digits is 20736, while the sum is 39.

The square root of 6681891 is about 2584.9353957111. The cubic root of 6681891 is about 188.3503633194.

The spelling of 6681891 in words is "six million, six hundred eighty-one thousand, eight hundred ninety-one".