28656540 has 144 divisors (see below), whose sum is σ = 97415136. Its totient is φ = 6758400.

The previous prime is 28656491. The next prime is 28656571. The reversal of 28656540 is 4565682.

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 = 28656495 and 28656504.

It is a congruent number.

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 47 ways as a sum of consecutive naturals, for example, 81004 + ... + 81356.

It is an arithmetic number, because the mean of its divisors is an integer number (676494).

Almost surely, 2^28656540 is an apocalyptic number.

28656540 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 28656540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48707568).

28656540 is an abundant number, since it is smaller than the sum of its proper divisors (68758596).

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

28656540 is a wasteful number, since it uses less digits than its factorization.

28656540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420 (or 415 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 28656540 is about 5353.1803631113. The cubic root of 28656540 is about 306.0139683486.

The spelling of 28656540 in words is "twenty-eight million, six hundred fifty-six thousand, five hundred forty".