28725840 has 400 divisors, whose sum is σ = 120992256. Its totient is φ = 6220800.

The previous prime is 28725833. The next prime is 28725847. The reversal of 28725840 is 4852782.

It is a happy number.

28725840 is a `hidden beast` number, since 2 + 8 + 72 + 584 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (28725833) and next prime (28725847).

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 = 28725795 and 28725804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28725847) by changing a digit.

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 79 ways as a sum of consecutive naturals, for example, 926625 + ... + 926655.

Almost surely, 2^28725840 is an apocalyptic number.

28725840 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 28725840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (60496128).

28725840 is an abundant number, since it is smaller than the sum of its proper divisors (92266416).

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

28725840 is a wasteful number, since it uses less digits than its factorization.

28725840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80 (or 65 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 36.

The square root of 28725840 is about 5359.6492422546. The cubic root of 28725840 is about 306.2604472349.

The spelling of 28725840 in words is "twenty-eight million, seven hundred twenty-five thousand, eight hundred forty".