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8720 = 245109
BaseRepresentation
bin10001000010000
3102221222
42020100
5234340
6104212
734265
oct21020
912858
108720
116608
125068
133c7a
14326c
1528b5
hex2210

8720 has 20 divisors (see below), whose sum is σ = 20460. Its totient is φ = 3456.

The previous prime is 8719. The next prime is 8731. The reversal of 8720 is 278.

Multipling 8720 by its sum of digits (17), we get a triangular number (148240 = T544).

Adding to 8720 its reverse (278), we get a palindrome (8998).

It can be written as a sum of positive squares in 2 ways, for example, as 4624 + 4096 = 68^2 + 64^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (17) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 10 and base 16.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 8720.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26 + ... + 134.

It is an arithmetic number, because the mean of its divisors is an integer number (1023).

8720 is a gapful number since it is divisible by the number (80) 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 8720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10230).

8720 is an abundant number, since it is smaller than the sum of its proper divisors (11740).

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

8720 is a wasteful number, since it uses less digits than its factorization.

8720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 8720 is about 93.3809402394. The cubic root of 8720 is about 20.5828493314.

The spelling of 8720 in words is "eight thousand, seven hundred twenty".

Divisors: 1 2 4 5 8 10 16 20 40 80 109 218 436 545 872 1090 1744 2180 4360 8720