28263505 has 4 divisors (see below), whose sum is σ = 33916212. Its totient is φ = 22610800.

The previous prime is 28263491. The next prime is 28263533. The reversal of 28263505 is 50536282.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50536282 = 2 ⋅25268141.

It can be written as a sum of positive squares in 2 ways, for example, as 7177041 + 21086464 = 2679^2 + 4592^2 .

It is not a de Polignac number, because 28263505 - 2⁷ = 28263377 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian 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, 2826346 + ... + 2826355.

It is an arithmetic number, because the mean of its divisors is an integer number (8479053).

Almost surely, 2^28263505 is an apocalyptic number.

It is an amenable number.

28263505 is a deficient number, since it is larger than the sum of its proper divisors (5652707).

28263505 is an equidigital number, since it uses as much as digits as its factorization.

28263505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5652706.

The product of its (nonzero) digits is 14400, while the sum is 31.

The square root of 28263505 is about 5316.3431981015. The cubic root of 28263505 is about 304.6084916597.

Adding to 28263505 its reverse (50536282), we get a palindrome (78799787).

The spelling of 28263505 in words is "twenty-eight million, two hundred sixty-three thousand, five hundred five".