20443 has 2 divisors, whose sum is σ = 20444.
Its totient is φ = 20442.
The previous prime is 20441. The next prime is 20477. The reversal of 20443 is 34402.
It is a weak prime.
It is a cyclic number.
It is not a de Polignac number, because 20443 - 21 = 20441 is a prime.
Together with 20441, it forms a pair of twin primes.
It is an Ulam number.
It is a nialpdrome in base 14.
It is not a weakly prime, because it can be changed into another prime (20441) 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 as a sum of consecutive naturals, namely, 10221 + 10222.
It is an arithmetic number, because the mean of its divisors is an integer number (10222).
220443 is an apocalyptic number.
20443 is a deficient number, since it is larger than the sum of its proper divisors (1).
20443 is an equidigital number, since it uses as much as digits as its factorization.
20443 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 96, while the sum is 13.
The square root of 20443 is about 142.9790194399.
The cubic root of 20443 is about 27.3431288839.
Adding to 20443 its reverse (34402), we get a palindrome (54845).
The spelling of 20443 in words is "twenty thousand, four hundred forty-three", and thus it is an iban number.