28091880 has 192 divisors, whose sum is σ = 101304000. Its totient is φ = 6905088.

The previous prime is 28091873. The next prime is 28091881. The reversal of 28091880 is 8819082.

28091880 = 294² + 295² + ... + 478².

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (28091881) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 759222 + ... + 759258.

It is an arithmetic number, because the mean of its divisors is an integer number (527625).

Almost surely, 2^28091880 is an apocalyptic number.

28091880 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 28091880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50652000).

28091880 is an abundant number, since it is smaller than the sum of its proper divisors (73212120).

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

28091880 is a wasteful number, since it uses less digits than its factorization.

28091880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 66 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 28091880 is about 5300.1773555231. The cubic root of 28091880 is about 303.9906795388.

The spelling of 28091880 in words is "twenty-eight million, ninety-one thousand, eight hundred eighty".