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BaseRepresentation
bin110110101110100
31102102210
412311310
51344040
6333420
7144456
oct66564
942383
1028020
111a063
1214270
13c9a5
14a2d6
158480
hex6d74

28020 has 24 divisors (see below), whose sum is σ = 78624. Its totient is φ = 7456.

The previous prime is 28019. The next prime is 28027. The reversal of 28020 is 2082.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an Ulam number.

It is a plaindrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 27987 and 28005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 174 + ... + 293.

It is an arithmetic number, because the mean of its divisors is an integer number (3276).

228020 is an apocalyptic number.

28020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28020 is an abundant number, since it is smaller than the sum of its proper divisors (50604).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39312).

28020 is a wasteful number, since it uses less digits than its factorization.

28020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 479 (or 477 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 28020 is about 167.3917560694. The cubic root of 28020 is about 30.3731179718.

It can be divided in two parts, 280 and 20, that added together give a triangular number (300 = T24).

The spelling of 28020 in words is "twenty-eight thousand, twenty".