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28728 = 2333719
BaseRepresentation
bin111000000111000
31110102000
413000320
51404403
6341000
7146520
oct70070
943360
1028728
111a647
1214760
13100cb
14a680
1587a3
hex7038

28728 has 64 divisors (see below), whose sum is σ = 96000. Its totient is φ = 7776.

The previous prime is 28723. The next prime is 28729. The reversal of 28728 is 82782.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1503 + ... + 1521.

It is an arithmetic number, because the mean of its divisors is an integer number (1500).

28728 is a Friedman number, since it can be written as (8+(8^2)^2)*7, using all its digits and the basic arithmetic operations.

228728 is an apocalyptic number.

28728 is a gapful number since it is divisible by the number (28) 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 28728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48000).

28728 is an abundant number, since it is smaller than the sum of its proper divisors (67272).

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

28728 is a wasteful number, since it uses less digits than its factorization.

28728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41 (or 31 counting only the distinct ones).

The product of its digits is 1792, while the sum is 27.

The square root of 28728 is about 169.4933627019. The cubic root of 28728 is about 30.6268123320.

The spelling of 28728 in words is "twenty-eight thousand, seven hundred twenty-eight".

Divisors: 1 2 3 4 6 7 8 9 12 14 18 19 21 24 27 28 36 38 42 54 56 57 63 72 76 84 108 114 126 133 152 168 171 189 216 228 252 266 342 378 399 456 504 513 532 684 756 798 1026 1064 1197 1368 1512 1596 2052 2394 3192 3591 4104 4788 7182 9576 14364 28728