28102500 has 90 divisors (see below), whose sum is σ = 88838750. Its totient is φ = 7488000.

The previous prime is 28102469. The next prime is 28102519. The reversal of 28102500 is 520182.

It can be written as a sum of positive squares in 5 ways, for example, as 12278016 + 15824484 = 3504^2 + 3978^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 21876 + ... + 23124.

Almost surely, 2^28102500 is an apocalyptic number.

28102500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28102500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44419375).

28102500 is an abundant number, since it is smaller than the sum of its proper divisors (60736250).

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

28102500 is a wasteful number, since it uses less digits than its factorization.

28102500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1279 (or 1259 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 28102500 is about 5301.1791141217. The cubic root of 28102500 is about 304.0289821168.

Adding to 28102500 its reverse (520182), we get a palindrome (28622682).

The spelling of 28102500 in words is "twenty-eight million, one hundred two thousand, five hundred".