28686240 has 144 divisors (see below), whose sum is σ = 106850016. Its totient is φ = 6950400.

The previous prime is 28686239. The next prime is 28686247. The reversal of 28686240 is 4268682.

28686240 is a `hidden beast` number, since 28 + 6 + 8 + 624 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28686195 and 28686204.

It is not an unprimeable number, because it can be changed into a prime (28686247) 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, 14935 + ... + 16745.

It is an arithmetic number, because the mean of its divisors is an integer number (742014).

Almost surely, 2^28686240 is an apocalyptic number.

28686240 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 28686240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53425008).

28686240 is an abundant number, since it is smaller than the sum of its proper divisors (78163776).

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

28686240 is a wasteful number, since it uses less digits than its factorization.

28686240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1843 (or 1832 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 28686240 is about 5355.9536965885. The cubic root of 28686240 is about 306.1196507608.

The spelling of 28686240 in words is "twenty-eight million, six hundred eighty-six thousand, two hundred forty".