28040040 has 128 divisors (see below), whose sum is σ = 106848000. Its totient is φ = 6407424.

The previous prime is 28040017. The next prime is 28040041. The reversal of 28040040 is 4004082.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 28039995 and 28040022.

It is not an unprimeable number, because it can be changed into a prime (28040041) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5706 + ... + 9414.

It is an arithmetic number, because the mean of its divisors is an integer number (834750).

Almost surely, 2^28040040 is an apocalyptic number.

28040040 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 28040040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53424000).

28040040 is an abundant number, since it is smaller than the sum of its proper divisors (78807960).

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

28040040 is a wasteful number, since it uses less digits than its factorization.

28040040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3736 (or 3726 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 28040040 is about 5295.2846948960. The cubic root of 28040040 is about 303.8035723220.

The spelling of 28040040 in words is "twenty-eight million, forty thousand, forty".