19903 has 4 divisors (see below), whose sum is σ = 21448. Its totient is φ = 18360.

The previous prime is 19891. The next prime is 19913. The reversal of 19903 is 30991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 30991 = 17 ⋅1823.

It is a cyclic number.

It is not a de Polignac number, because 19903 - 2⁹ = 19391 is a prime.

It is a super-2 number, since 2×19903² = 792258818, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 8.

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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 753 + ... + 778.

It is an arithmetic number, because the mean of its divisors is an integer number (5362).

2¹⁹⁹⁰³ is an apocalyptic number.

19903 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

19903 is a deficient number, since it is larger than the sum of its proper divisors (1545).

19903 is a wasteful number, since it uses less digits than its factorization.

19903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1544.

The product of its (nonzero) digits is 243, while the sum is 22.

The square root of 19903 is about 141.0779926140. The cubic root of 19903 is about 27.1002219451.

Subtracting from 19903 its sum of digits (22), we obtain a square (19881 = 141²).

The spelling of 19903 in words is "nineteen thousand, nine hundred three".