28993 has 4 divisors (see below), whose sum is σ = 29440. Its totient is φ = 28548.

The previous prime is 28979. The next prime is 29009. The reversal of 28993 is 39982.

It is a happy number.

28993 is nontrivially palindromic in base 12.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 39982 = 2 ⋅19991.

It is a cyclic number.

It is not a de Polignac number, because 28993 - 2⁵ = 28961 is a prime.

It is a Duffinian number.

28993 is a lucky number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28933) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105 + ... + 262.

It is an arithmetic number, because the mean of its divisors is an integer number (7360).

2²⁸⁹⁹³ is an apocalyptic number.

It is an amenable number.

28993 is a deficient number, since it is larger than the sum of its proper divisors (447).

28993 is an equidigital number, since it uses as much as digits as its factorization.

28993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446.

The product of its digits is 3888, while the sum is 31.

The square root of 28993 is about 170.2733097112. The cubic root of 28993 is about 30.7206960789.

The spelling of 28993 in words is "twenty-eight thousand, nine hundred ninety-three".