1686 has 8 divisors (see below), whose sum is σ = 3384. Its totient is φ = 560.

The previous prime is 1669. The next prime is 1693. The reversal of 1686 is 6861.

1686 = 19^{2} + 20^{2} + ... + 22^{2}.

1686 is nontrivially palindromic in base 13 and base 16.

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

1686 is an admirable number.

1686 is an undulating number in base 13 and base 16.

It is a Curzon number.

It is a nialpdrome in base 12, base 14 and base 15.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135 + ... + 146.

It is an arithmetic number, because the mean of its divisors is an integer number (423).

1686 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1692).

1686 is a wasteful number, since it uses less digits than its factorization.

1686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286.

The product of its digits is 288, while the sum is 21.

The square root of 1686 is about 41.0609303353. The cubic root of 1686 is about 11.9019792861.

The spelling of 1686 in words is "one thousand, six hundred eighty-six".

• e-mail: info -at- numbersaplenty.com • Privacy notice • done in 0.104 sec. • engine limits •