28813 has 2 divisors, whose sum is σ = 28814. Its totient is φ = 28812.

The previous prime is 28807. The next prime is 28817. The reversal of 28813 is 31882.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20164 + 8649 = 142^2 + 93^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14406 + 14407.

It is an arithmetic number, because the mean of its divisors is an integer number (14407).

2²⁸⁸¹³ is an apocalyptic number.

It is an amenable number.

28813 is a deficient number, since it is larger than the sum of its proper divisors (1).

28813 is an equidigital number, since it uses as much as digits as its factorization.

28813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 22.

The square root of 28813 is about 169.7439247808. The cubic root of 28813 is about 30.6569886495.

It can be divided in two parts, 28 and 813, that added together give a square (841 = 29²).

The spelling of 28813 in words is "twenty-eight thousand, eight hundred thirteen".