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28125 = 3255
BaseRepresentation
bin110110111011101
31102120200
412313131
51400000
6334113
7144666
oct66735
942520
1028125
111a149
1214339
13ca56
14a36d
158500
hex6ddd

28125 has 18 divisors (see below), whose sum is σ = 50778. Its totient is φ = 15000.

The previous prime is 28123. The next prime is 28151. The reversal of 28125 is 52182.

It can be divided in two parts, 28 and 125, that added together give a triangular number (153 = T17).

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 3 ways, for example, as 12996 + 15129 = 114^2 + 123^2 .

It is not a de Polignac number, because 28125 - 21 = 28123 is a prime.

Its product of digits (160) is a multiple of the sum of its prime divisors (8).

It is a plaindrome in base 7 and base 16.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 28098 and 28107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28123) 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 17 ways as a sum of consecutive naturals, for example, 5623 + ... + 5627.

It is an arithmetic number, because the mean of its divisors is an integer number (2821).

228125 is an apocalyptic number.

28125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28125 is the 90-th nonagonal number.

It is an amenable number.

28125 is a deficient number, since it is larger than the sum of its proper divisors (22653).

28125 is an frugal number, since it uses more digits than its factorization.

28125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31 (or 8 counting only the distinct ones).

The product of its digits is 160, while the sum is 18.

The square root of 28125 is about 167.7050983125. The cubic root of 28125 is about 30.4110099779.

The spelling of 28125 in words is "twenty-eight thousand, one hundred twenty-five".

Divisors: 1 3 5 9 15 25 45 75 125 225 375 625 1125 1875 3125 5625 9375 28125