28805813 has 4 divisors (see below), whose sum is σ = 28881408. Its totient is φ = 28730220.

The previous prime is 28805809. The next prime is 28805827. The reversal of 28805813 is 31850882.

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.

It is a cyclic number.

It is not a de Polignac number, because 28805813 - 2² = 28805809 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28805893) 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, 37223 + ... + 37988.

It is an arithmetic number, because the mean of its divisors is an integer number (7220352).

Almost surely, 2^28805813 is an apocalyptic number.

It is an amenable number.

28805813 is a deficient number, since it is larger than the sum of its proper divisors (75595).

28805813 is an equidigital number, since it uses as much as digits as its factorization.

28805813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75594.

The product of its (nonzero) digits is 15360, while the sum is 35.

The square root of 28805813 is about 5367.1047129714. The cubic root of 28805813 is about 306.5443945179.

The spelling of 28805813 in words is "twenty-eight million, eight hundred five thousand, eight hundred thirteen".