1993 has 2 divisors, whose sum is σ = 1994.
Its totient is φ = 1992.
The previous prime is 1987. The next prime is 1997. The reversal of 1993 is 3991.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 1849 + 144 = 43^2 + 12^2
It is a cyclic number.
It is not a de Polignac number, because 1993 - 29 = 1481 is a prime.
It is a plaindrome in base 15.
It is a nialpdrome in base 13.
It is not a weakly prime, because it can be changed into another prime (1997) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a good prime.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 996 + 997.
It is an arithmetic number, because the mean of its divisors is an integer number (997).
It is an amenable number.
1993 is a deficient number, since it is larger than the sum of its proper divisors (1).
1993 is an equidigital number, since it uses as much as digits as its factorization.
1993 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 243, while the sum is 22.
The square root of 1993 is about 44.6430285711.
The cubic root of 1993 is about 12.5844942377.
It can be divided in two parts, 199 and 3, that added together give a palindrome (202).
The spelling of 1993 in words is "one thousand, nine hundred ninety-three".