19806 has 8 divisors (see below), whose sum is σ = 39624. Its totient is φ = 6600.

The previous prime is 19801. The next prime is 19813. The reversal of 19806 is 60891.

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

19806 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1645 + ... + 1656.

It is an arithmetic number, because the mean of its divisors is an integer number (4953).

2¹⁹⁸⁰⁶ is an apocalyptic number.

19806 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 (19812).

19806 is a wasteful number, since it uses less digits than its factorization.

19806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3306.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 19806 is about 140.7337912514. The cubic root of 19806 is about 27.0561246799.

The spelling of 19806 in words is "nineteen thousand, eight hundred six".