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18580 = 225929
BaseRepresentation
bin100100010010100
3221111011
410202110
51043310
6222004
7105112
oct44224
927434
1018580
1112a61
12a904
1385c3
146ab2
15578a
hex4894

18580 has 12 divisors (see below), whose sum is σ = 39060. Its totient is φ = 7424.

The previous prime is 18553. The next prime is 18583. The reversal of 18580 is 8581.

It can be written as a sum of positive squares in 2 ways, for example, as 2704 + 15876 = 52^2 + 126^2 .

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18583) by changing a digit.

18580 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 445 + ... + 484.

It is an arithmetic number, because the mean of its divisors is an integer number (3255).

218580 is an apocalyptic number.

18580 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18580 is an abundant number, since it is smaller than the sum of its proper divisors (20480).

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 (19530).

18580 is a wasteful number, since it uses less digits than its factorization.

18580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 938 (or 936 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 18580 is about 136.3084736911. The cubic root of 18580 is about 26.4859305878.

Subtracting from 18580 its reverse (8581), we obtain a palindrome (9999).

It can be divided in two parts, 18 and 580, that multiplied together give a triangular number (10440 = T144).

The spelling of 18580 in words is "eighteen thousand, five hundred eighty".

Divisors: 1 2 4 5 10 20 929 1858 3716 4645 9290 18580