6681643 has 4 divisors (see below), whose sum is σ = 6695280. Its totient is φ = 6668008.

The previous prime is 6681637. The next prime is 6681671. The reversal of 6681643 is 3461866.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6681643 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6681599 and 6681608.

It is not an unprimeable number, because it can be changed into a prime (6681683) 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 3 ways as a sum of consecutive naturals, for example, 6055 + ... + 7072.

It is an arithmetic number, because the mean of its divisors is an integer number (1673820).

Almost surely, 2^6681643 is an apocalyptic number.

6681643 is a deficient number, since it is larger than the sum of its proper divisors (13637).

6681643 is a wasteful number, since it uses less digits than its factorization.

6681643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13636.

The product of its digits is 20736, while the sum is 34.

The square root of 6681643 is about 2584.8874250149. The cubic root of 6681643 is about 188.3480330674.

The spelling of 6681643 in words is "six million, six hundred eighty-one thousand, six hundred forty-three".