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20480 = 2125
BaseRepresentation
bin101000000000000
31001002112
411000000
51123410
6234452
7113465
oct50000
931075
1020480
1114429
12ba28
139425
14766c
156105
hex5000

20480 has 26 divisors (see below), whose sum is σ = 49146. Its totient is φ = 8192.

The previous prime is 20479. The next prime is 20483. The reversal of 20480 is 8402.

Adding to 20480 its reverse (8402), we get a palindrome (28882).

20480 = T88 + T89 + ... + T92.

It can be written as a sum of positive squares in only one way, i.e., 16384 + 4096 = 128^2 + 64^2 .

It is an Ulam number.

It is a nialpdrome in base 4, base 8 and base 16.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (2) of ones.

In principle, a polygon with 20480 sides can be constructed with ruler and compass.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4094 + ... + 4098.

220480 is an apocalyptic number.

20480 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 20480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24573).

20480 is an abundant number, since it is smaller than the sum of its proper divisors (28666).

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

20480 is an frugal number, since it uses more digits than its factorization.

20480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29 (or 7 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 20480 is about 143.1083505600. The cubic root of 20480 is about 27.3596151468.

The spelling of 20480 in words is "twenty thousand, four hundred eighty".

Divisors: 1 2 4 5 8 10 16 20 32 40 64 80 128 160 256 320 512 640 1024 1280 2048 2560 4096 5120 10240 20480