28128525 has 24 divisors (see below), whose sum is σ = 46931520. Its totient is φ = 14864640.

The previous prime is 28128491. The next prime is 28128533. The reversal of 28128525 is 52582182.

It is not a de Polignac number, because 28128525 - 2¹⁰ = 28127501 is a prime.

It is a congruent number.

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, 6816 + ... + 10134.

It is an arithmetic number, because the mean of its divisors is an integer number (1955480).

Almost surely, 2^28128525 is an apocalyptic number.

28128525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28128525 is a deficient number, since it is larger than the sum of its proper divisors (18802995).

28128525 is a wasteful number, since it uses less digits than its factorization.

28128525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3445 (or 3440 counting only the distinct ones).

The product of its digits is 12800, while the sum is 33.

The square root of 28128525 is about 5303.6331886736. The cubic root of 28128525 is about 304.1228042921.

The spelling of 28128525 in words is "twenty-eight million, one hundred twenty-eight thousand, five hundred twenty-five".