21383 has 2 divisors, whose sum is σ = 21384.
Its totient is φ = 21382.
The previous prime is 21379. The next prime is 21391. The reversal of 21383 is 38312.
Adding to 21383 its reverse (38312), we get a palindrome (59695).
It can be divided in two parts, 21 and 383, that added together give a palindrome (404).
It is a weak prime.
It is a cyclic number.
It is not a de Polignac number, because 21383 - 22 = 21379 is a prime.
It is a Sophie Germain prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (21313) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10691 + 10692.
It is an arithmetic number, because the mean of its divisors is an integer number (10692).
221383 is an apocalyptic number.
21383 is a deficient number, since it is larger than the sum of its proper divisors (1).
21383 is an equidigital number, since it uses as much as digits as its factorization.
21383 is an evil number, because the sum of its binary digits is even.
The product of its digits is 144, while the sum is 17.
The square root of 21383 is about 146.2292720354.
The cubic root of 21383 is about 27.7559573823.
The spelling of 21383 in words is "twenty-one thousand, three hundred eighty-three".