28117225 has 24 divisors (see below), whose sum is σ = 36258840. Its totient is φ = 21611520.

The previous prime is 28117213. The next prime is 28117231. The reversal of 28117225 is 52271182.

It can be written as a sum of positive squares in 12 ways, for example, as 17147881 + 10969344 = 4141^2 + 3312^2 .

It is not a de Polignac number, because 28117225 - 2⁷ = 28117097 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28117193 and 28117202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 104391 + ... + 104659.

It is an arithmetic number, because the mean of its divisors is an integer number (1510785).

Almost surely, 2^28117225 is an apocalyptic number.

28117225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28117225 is a deficient number, since it is larger than the sum of its proper divisors (8141615).

28117225 is a wasteful number, since it uses less digits than its factorization.

28117225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429 (or 424 counting only the distinct ones).

The product of its digits is 2240, while the sum is 28.

The square root of 28117225 is about 5302.5677742015. The cubic root of 28117225 is about 304.0820740135.

The spelling of 28117225 in words is "twenty-eight million, one hundred seventeen thousand, two hundred twenty-five".