28531225 has 24 divisors (see below), whose sum is σ = 36740952. Its totient is φ = 21964800.

The previous prime is 28531189. The next prime is 28531249. The reversal of 28531225 is 52213582.

It can be written as a sum of positive squares in 12 ways, for example, as 13808656 + 14722569 = 3716^2 + 3837^2 .

It is not a de Polignac number, because 28531225 - 2¹⁷ = 28400153 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28531193 and 28531202.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80649 + ... + 81001.

It is an arithmetic number, because the mean of its divisors is an integer number (1530873).

Almost surely, 2^28531225 is an apocalyptic number.

28531225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28531225 is a deficient number, since it is larger than the sum of its proper divisors (8209727).

28531225 is a wasteful number, since it uses less digits than its factorization.

28531225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 477 (or 472 counting only the distinct ones).

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

The square root of 28531225 is about 5341.4628146230. The cubic root of 28531225 is about 305.5672503635.

The spelling of 28531225 in words is "twenty-eight million, five hundred thirty-one thousand, two hundred twenty-five".