28508813 has 8 divisors (see below), whose sum is σ = 30232440. Its totient is φ = 26790400.

The previous prime is 28508807. The next prime is 28508819. The reversal of 28508813 is 31880582.

It is an interprime number because it is at equal distance from previous prime (28508807) and next prime (28508819).

It can be written as a sum of positive squares in 4 ways, for example, as 3087049 + 25421764 = 1757^2 + 5042^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28508813 - 2¹⁰ = 28507789 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 (28508819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21263 + ... + 22563.

It is an arithmetic number, because the mean of its divisors is an integer number (3779055).

Almost surely, 2^28508813 is an apocalyptic number.

It is an amenable number.

28508813 is a deficient number, since it is larger than the sum of its proper divisors (1723627).

28508813 is a wasteful number, since it uses less digits than its factorization.

28508813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2607.

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

The square root of 28508813 is about 5339.3644752910. The cubic root of 28508813 is about 305.4872191324.

The spelling of 28508813 in words is "twenty-eight million, five hundred eight thousand, eight hundred thirteen".