28205880 has 128 divisors (see below), whose sum is σ = 90720000. Its totient is φ = 6994944.

The previous prime is 28205857. The next prime is 28205897. The reversal of 28205880 is 8850282.

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 31 ways as a sum of consecutive naturals, for example, 202851 + ... + 202989.

It is an arithmetic number, because the mean of its divisors is an integer number (708750).

Almost surely, 2^28205880 is an apocalyptic number.

28205880 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 28205880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45360000).

28205880 is an abundant number, since it is smaller than the sum of its proper divisors (62514120).

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

28205880 is a wasteful number, since it uses less digits than its factorization.

28205880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 33.

The square root of 28205880 is about 5310.9208241133. The cubic root of 28205880 is about 304.4013339698.

The spelling of 28205880 in words is "twenty-eight million, two hundred five thousand, eight hundred eighty".