15993 has 6 divisors (see below), whose sum is σ = 23114. Its totient is φ = 10656.

The previous prime is 15991. The next prime is 16001. The reversal of 15993 is 39951.

15993 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 13689 + 2304 = 117^2 + 48^2 .

It is not a de Polignac number, because 15993 - 2¹ = 15991 is a prime.

It is a Duffinian number.

15993 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (15991) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 880 + ... + 897.

2¹⁵⁹⁹³ is an apocalyptic number.

It is an amenable number.

15993 is a deficient number, since it is larger than the sum of its proper divisors (7121).

15993 is a wasteful number, since it uses less digits than its factorization.

15993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1783 (or 1780 counting only the distinct ones).

The product of its digits is 1215, while the sum is 27.

The square root of 15993 is about 126.4634334501. The cubic root of 15993 is about 25.1947456921.

It can be divided in two parts, 159 and 93, that added together give a palindrome (252).

The spelling of 15993 in words is "fifteen thousand, nine hundred ninety-three".