6891681 has 8 divisors (see below), whose sum is σ = 9729504. Its totient is φ = 4324160.

The previous prime is 6891673. The next prime is 6891691. The reversal of 6891681 is 1861986.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6891681 - 2³ = 6891673 is a prime.

It is a super-2 number, since 2×6891681² = 94990534011522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (6891601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67515 + ... + 67616.

It is an arithmetic number, because the mean of its divisors is an integer number (1216188).

Almost surely, 2^6891681 is an apocalyptic number.

It is an amenable number.

6891681 is a deficient number, since it is larger than the sum of its proper divisors (2837823).

6891681 is a wasteful number, since it uses less digits than its factorization.

6891681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135151.

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

The square root of 6891681 is about 2625.2011351514. The cubic root of 6891681 is about 190.3012856143.

The spelling of 6891681 in words is "six million, eight hundred ninety-one thousand, six hundred eighty-one".