28253215 has 4 divisors (see below), whose sum is σ = 33903864. Its totient is φ = 22602568.

The previous prime is 28253207. The next prime is 28253233. The reversal of 28253215 is 51235282.

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 28253215 - 2³ = 28253207 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, 2825317 + ... + 2825326.

It is an arithmetic number, because the mean of its divisors is an integer number (8475966).

Almost surely, 2^28253215 is an apocalyptic number.

28253215 is a deficient number, since it is larger than the sum of its proper divisors (5650649).

28253215 is an equidigital number, since it uses as much as digits as its factorization.

28253215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5650648.

The product of its digits is 4800, while the sum is 28.

The square root of 28253215 is about 5315.3753395221. The cubic root of 28253215 is about 304.5715205215.

Adding to 28253215 its reverse (51235282), we get a palindrome (79488497).

The spelling of 28253215 in words is "twenty-eight million, two hundred fifty-three thousand, two hundred fifteen".