28073640 has 128 divisors (see below), whose sum is σ = 101376000. Its totient is φ = 6075648.

The previous prime is 28073627. The next prime is 28073651. The reversal of 28073640 is 4637082.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 28073598 and 28073607.

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, 15081 + ... + 16839.

It is an arithmetic number, because the mean of its divisors is an integer number (792000).

Almost surely, 2^28073640 is an apocalyptic number.

28073640 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 28073640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50688000).

28073640 is an abundant number, since it is smaller than the sum of its proper divisors (73302360).

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

28073640 is a wasteful number, since it uses less digits than its factorization.

28073640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1799 (or 1795 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 28073640 is about 5298.4563789844. The cubic root of 28073640 is about 303.9248717858.

It can be divided in two parts, 280 and 73640, that added together give a triangular number (73920 = T₃₈₄).

The spelling of 28073640 in words is "twenty-eight million, seventy-three thousand, six hundred forty".