28190815 has 4 divisors (see below), whose sum is σ = 33828984. Its totient is φ = 22552648.

The previous prime is 28190809. The next prime is 28190837. The reversal of 28190815 is 51809182.

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

It is a cyclic number.

It is not a de Polignac number, because 28190815 - 2¹⁵ = 28158047 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, 2819077 + ... + 2819086.

It is an arithmetic number, because the mean of its divisors is an integer number (8457246).

Almost surely, 2^28190815 is an apocalyptic number.

28190815 is a deficient number, since it is larger than the sum of its proper divisors (5638169).

28190815 is an equidigital number, since it uses as much as digits as its factorization.

28190815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5638168.

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 28190815 is about 5309.5023307274. The cubic root of 28190815 is about 304.3471298727.

Adding to 28190815 its reverse (51809182), we get a palindrome (79999997).

The spelling of 28190815 in words is "twenty-eight million, one hundred ninety thousand, eight hundred fifteen".