28188500 has 24 divisors (see below), whose sum is σ = 61564776. Its totient is φ = 11275200.

The previous prime is 28188497. The next prime is 28188509. The reversal of 28188500 is 588182.

It can be written as a sum of positive squares in 4 ways, for example, as 7376656 + 20811844 = 2716^2 + 4562^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28188509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27689 + ... + 28688.

It is an arithmetic number, because the mean of its divisors is an integer number (2565199).

Almost surely, 2^28188500 is an apocalyptic number.

28188500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28188500 is an abundant number, since it is smaller than the sum of its proper divisors (33376276).

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

28188500 is a wasteful number, since it uses less digits than its factorization.

28188500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56396 (or 56384 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 32.

The square root of 28188500 is about 5309.2843208854. The cubic root of 28188500 is about 304.3387987562.

The spelling of 28188500 in words is "twenty-eight million, one hundred eighty-eight thousand, five hundred".