28512005 has 4 divisors (see below), whose sum is σ = 34214412. Its totient is φ = 22809600.

The previous prime is 28511993. The next prime is 28512013. The reversal of 28512005 is 50021582.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15888196 + 12623809 = 3986^2 + 3553^2 .

It is not a de Polignac number, because 28512005 - 2¹² = 28507909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2851196 + ... + 2851205.

It is an arithmetic number, because the mean of its divisors is an integer number (8553603).

Almost surely, 2^28512005 is an apocalyptic number.

It is an amenable number.

28512005 is a deficient number, since it is larger than the sum of its proper divisors (5702407).

28512005 is an equidigital number, since it uses as much as digits as its factorization.

28512005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5702406.

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 28512005 is about 5339.6633789032. The cubic root of 28512005 is about 305.4986200375.

Adding to 28512005 its reverse (50021582), we get a palindrome (78533587).

The spelling of 28512005 in words is "twenty-eight million, five hundred twelve thousand, five".