28100538 has 24 divisors (see below), whose sum is σ = 62531508. Its totient is φ = 9113472.

The previous prime is 28100531. The next prime is 28100551. The reversal of 28100538 is 83500182.

It is a happy number.

28100538 is a `hidden beast` number, since 28 + 100 + 538 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 26286129 + 1814409 = 5127^2 + 1347^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28100531) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20431 + ... + 21762.

Almost surely, 2^28100538 is an apocalyptic number.

28100538 is an abundant number, since it is smaller than the sum of its proper divisors (34430970).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28100538 is a wasteful number, since it uses less digits than its factorization.

28100538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42238 (or 42235 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 28100538 is about 5300.9940577216. The cubic root of 28100538 is about 304.0219066046.

The spelling of 28100538 in words is "twenty-eight million, one hundred thousand, five hundred thirty-eight".