19986 has 8 divisors (see below), whose sum is σ = 39984. Its totient is φ = 6660.

The previous prime is 19979. The next prime is 19991. The reversal of 19986 is 68991.

It is a happy number.

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

19986 is an admirable 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, 1660 + ... + 1671.

It is an arithmetic number, because the mean of its divisors is an integer number (4998).

2¹⁹⁹⁸⁶ is an apocalyptic number.

19986 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 (19992).

19986 is a wasteful number, since it uses less digits than its factorization.

19986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3336.

The product of its digits is 3888, while the sum is 33.

The square root of 19986 is about 141.3718500975. The cubic root of 19986 is about 27.1378410464.

The spelling of 19986 in words is "nineteen thousand, nine hundred eighty-six".