19918 has 8 divisors (see below), whose sum is σ = 31248. Its totient is φ = 9504.

The previous prime is 19913. The next prime is 19919. The reversal of 19918 is 81991.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19913) 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, 171 + ... + 262.

It is an arithmetic number, because the mean of its divisors is an integer number (3906).

2¹⁹⁹¹⁸ is an apocalyptic number.

19918 is a deficient number, since it is larger than the sum of its proper divisors (11330).

19918 is a wasteful number, since it uses less digits than its factorization.

19918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458.

The product of its digits is 648, while the sum is 28.

The square root of 19918 is about 141.1311446847. The cubic root of 19918 is about 27.1070283101.

The spelling of 19918 in words is "nineteen thousand, nine hundred eighteen".