19321 has 3 divisors (see below), whose sum is σ = 19461.
Its totient is φ = 19182.
The previous prime is 19319. The next prime is 19333. The reversal of 19321 is 12391.
19321 = T138 + T139.
The square root of 19321 is 139.
It is a perfect power (a square), and thus also a powerful number.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.
It is not a de Polignac number, because 19321 - 21 = 19319 is a prime.
It is a Duffinian number.
It is a nialpdrome in base 12.
It is a junction number, because it is equal to n+sod(n) for n = 19295 and 19304.
It is not an unprimeable number, because it can be changed into a prime (19301) by changing a digit.
It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 70 + ... + 208.
It is an arithmetic number, because the mean of its divisors is an integer number (6487).
19321 is a Friedman number, since it can be written as 139^(2*1), using all its digits and the basic arithmetic operations.
219321 is an apocalyptic number.
19321 is the 139-th square number.
19321 is the 70-th centered octagonal number.
It is an amenable number.
19321 is a deficient number, since it is larger than the sum of its proper divisors (140).
19321 is an frugal number, since it uses more digits than its factorization.
19321 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 278 (or 139 counting only the distinct ones).
The product of its digits is 54, while the sum is 16.
The cubic root of 19321 is about 26.8334512124.
Multiplying 19321 by its sum of digits (16), we get a square (309136 = 5562).
The spelling of 19321 in words is "nineteen thousand, three hundred twenty-one".