28251215 has 16 divisors (see below), whose sum is σ = 35060256. Its totient is φ = 21840000.

The previous prime is 28251211. The next prime is 28251217. The reversal of 28251215 is 51215282.

It is not a de Polignac number, because 28251215 - 2² = 28251211 is a prime.

It is a super-2 number, since 2×28251215² = 1596262297952450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28251211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21065 + ... + 22365.

It is an arithmetic number, because the mean of its divisors is an integer number (2191266).

Almost surely, 2^28251215 is an apocalyptic number.

28251215 is a deficient number, since it is larger than the sum of its proper divisors (6809041).

28251215 is a wasteful number, since it uses less digits than its factorization.

28251215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1450.

The product of its digits is 1600, while the sum is 26.

The square root of 28251215 is about 5315.1872027239. The cubic root of 28251215 is about 304.5643336413.

Adding to 28251215 its reverse (51215282), we get a palindrome (79466497).

The spelling of 28251215 in words is "twenty-eight million, two hundred fifty-one thousand, two hundred fifteen".