28724040 has 96 divisors (see below), whose sum is σ = 94718520. Its totient is φ = 7547904.

The previous prime is 28724027. The next prime is 28724041. The reversal of 28724040 is 4042782.

It can be written as a sum of positive squares in 4 ways, for example, as 28451556 + 272484 = 5334^2 + 522^2 .

It is a junction number, because it is equal to n+sod(n) for n = 28723995 and 28724013.

It is not an unprimeable number, because it can be changed into a prime (28724041) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25734 + ... + 26826.

Almost surely, 2^28724040 is an apocalyptic number.

28724040 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 28724040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47359260).

28724040 is an abundant number, since it is smaller than the sum of its proper divisors (65994480).

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

28724040 is a wasteful number, since it uses less digits than its factorization.

28724040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1183 (or 1176 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 27.

The square root of 28724040 is about 5359.4813181874. The cubic root of 28724040 is about 306.2540502033.

The spelling of 28724040 in words is "twenty-eight million, seven hundred twenty-four thousand, forty".