28285440 has 160 divisors (see below), whose sum is σ = 94279680. Its totient is φ = 7225344.

The previous prime is 28285417. The next prime is 28285451. The reversal of 28285440 is 4458282.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (160).

It is a super-2 number, since 2×28285440² = 1600132231987200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 222657 + ... + 222783.

It is an arithmetic number, because the mean of its divisors is an integer number (589248).

Almost surely, 2^28285440 is an apocalyptic number.

28285440 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 28285440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47139840).

28285440 is an abundant number, since it is smaller than the sum of its proper divisors (65994240).

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

28285440 is a wasteful number, since it uses less digits than its factorization.

28285440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182 (or 166 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 33.

The square root of 28285440 is about 5318.4057761701. The cubic root of 28285440 is about 304.6872723996.

The spelling of 28285440 in words is "twenty-eight million, two hundred eighty-five thousand, four hundred forty".