28910840 has 64 divisors (see below), whose sum is σ = 75340800. Its totient is φ = 9779328.

The previous prime is 28910831. The next prime is 28910851. The reversal of 28910840 is 4801982.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 28910797 and 28910806.

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 15 ways as a sum of consecutive naturals, for example, 21467 + ... + 22773.

It is an arithmetic number, because the mean of its divisors is an integer number (1177200).

Almost surely, 2^28910840 is an apocalyptic number.

28910840 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 28910840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37670400).

28910840 is an abundant number, since it is smaller than the sum of its proper divisors (46429960).

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

28910840 is a wasteful number, since it uses less digits than its factorization.

28910840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1404 (or 1400 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 28910840 is about 5376.8801362872. The cubic root of 28910840 is about 306.9164998359.

The spelling of 28910840 in words is "twenty-eight million, nine hundred ten thousand, eight hundred forty".