19947 has 8 divisors (see below), whose sum is σ = 27280. Its totient is φ = 12960.

The previous prime is 19937. The next prime is 19949. The reversal of 19947 is 74991.

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

It is not a de Polignac number, because 19947 - 2⁷ = 19819 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 19947.

It is not an unprimeable number, because it can be changed into a prime (19949) 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, 129 + ... + 237.

It is an arithmetic number, because the mean of its divisors is an integer number (3410).

2¹⁹⁹⁴⁷ is an apocalyptic number.

19947 is a deficient number, since it is larger than the sum of its proper divisors (7333).

19947 is a wasteful number, since it uses less digits than its factorization.

19947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173.

The product of its digits is 2268, while the sum is 30.

The square root of 19947 is about 141.2338486341. The cubic root of 19947 is about 27.1201775991.

The spelling of 19947 in words is "nineteen thousand, nine hundred forty-seven".