28431225 has 36 divisors (see below), whose sum is σ = 53926236. Its totient is φ = 14269440.

The previous prime is 28431217. The next prime is 28431229. The reversal of 28431225 is 52213482.

28431225 is a `hidden beast` number, since 2 + 8 + 431 + 225 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 1929321 + 26501904 = 1389^2 + 5148^2 .

It is not a de Polignac number, because 28431225 - 2³ = 28431217 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28431229) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 109 + ... + 7541.

It is an arithmetic number, because the mean of its divisors is an integer number (1497951).

Almost surely, 2^28431225 is an apocalyptic number.

28431225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28431225 is a deficient number, since it is larger than the sum of its proper divisors (25495011).

28431225 is a wasteful number, since it uses less digits than its factorization.

28431225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7466 (or 7458 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 28431225 is about 5332.0938663906. The cubic root of 28431225 is about 305.2098350001.

The spelling of 28431225 in words is "twenty-eight million, four hundred thirty-one thousand, two hundred twenty-five".