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28000000 = 28567
BaseRepresentation
bin110101011001…
…1111100000000
31221200112210001
41222303330000
524132000000
62440045344
7456665440
oct152637400
957615701
1028000000
11148948a6
129463854
135a54862
143a0c120
1526d146a
hex1ab3f00

28000000 has 126 divisors (see below), whose sum is σ = 79842728. Its totient is φ = 9600000.

The previous prime is 27999943. The next prime is 28000019. The reversal of 28000000 is 82.

Adding to 28000000 its reverse (82), we get a palindrome (28000082).

It can be divided in two parts, 2 and 8000000, that multiplied together give a square (16000000 = 40002).

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 3999997 + ... + 4000003.

Almost surely, 228000000 is an apocalyptic number.

28000000 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 28000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39921364).

28000000 is an abundant number, since it is smaller than the sum of its proper divisors (51842728).

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

28000000 is an frugal number, since it uses more digits than its factorization.

28000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53 (or 14 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 28000000 is about 5291.5026221292. The cubic root of 28000000 is about 303.6588971876.

The spelling of 28000000 in words is "twenty-eight million", and thus it is an aban number and an uban number.

Divisors: 1 2 4 5 7 8 10 14 16 20 25 28 32 35 40 50 56 64 70 80 100 112 125 128 140 160 175 200 224 250 256 280 320 350 400 448 500 560 625 640 700 800 875 896 1000 1120 1250 1280 1400 1600 1750 1792 2000 2240 2500 2800 3125 3200 3500 4000 4375 4480 5000 5600 6250 6400 7000 8000 8750 8960 10000 11200 12500 14000 15625 16000 17500 20000 21875 22400 25000 28000 31250 32000 35000 40000 43750 44800 50000 56000 62500 70000 80000 87500 100000 109375 112000 125000 140000 160000 175000 200000 218750 224000 250000 280000 350000 400000 437500 500000 560000 700000 800000 875000 1000000 1120000 1400000 1750000 2000000 2800000 3500000 4000000 5600000 7000000 14000000 28000000