# How Do You Find An Amicable Number?

## What is an example of a friendly number?

An addition/subtraction strategy that uses a number that is easy to work from, typically 10 or a multiple of 10.

For example, to solve 16 – 9, one might recognize that the friendly number 10 is 6 less than 16, then count down 1 more to 9 to find that the difference is 7..

## Who invented amicable numbers?

Amicable numbers were known to the Pythagoreans, who credited them with many mystical properties. A general formula by which some of these numbers could be derived was invented circa 850 by the Iraqi mathematician Thābit ibn Qurra (826–901).

## Are 1184 and 1210 amicable numbers?

Almost perfect number pairs are pairs of numbers that equal the sum of their partner’s divisors. For example, 1184 and 1210 are an almost perfect number pair. 1184 = 1+2+5+10+11+22+55+110+121+242+605, the sum of the divisors of 1210. … The set of numbers requested, above, are amicable numbers if they come in pairs.

## Why is 28 the perfect number?

A number is perfect if all of its factors, including 1 but excluding itself, perfectly add up to the number you began with. 6, for example, is perfect, because its factors — 3, 2, and 1 — all sum up to 6. 28 is perfect too: 14, 7, 4, 2, and 1 add up to 28.

## Is 1 a special number?

The number one is far more special than a prime! It is the unit (the building block) of the positive integers, hence the only integer which merits its own existence axiom in Peano’s axioms. … It is the only perfect nth power for all positive integers n. It is the only positive integer with exactly one positive divisor.

## Is 496 a amicable number?

A perfect number is a cycle of length 1 of s, i.e., a number whose positive divisors (except for itself) sum to itself. For example, 6 is perfect (1+2+3=6), and in fact 6 is the smallest perfect number. The next two perfect numbers are 28 (1+2+4+7+14=28) and 496 (1+2+4+8+16+31+62+124+248=496).

## What are special numbers?

Special Numbers in Java are ones whose sum of factorials of digits is equal to the number itself. It can be an N digit number. The program has to first break the number into its corresponding digits and calculate their factorials. … If the sum matches the original number then the number is called to be a Special number.

## WHY IS 496 a perfect number?

Also related to its being a perfect number, 496 is a harmonic divisor number, since the number of proper divisors of 496 divided by the sum of the reciprocals of its divisors, 1, 2, 4, 8, 16, 31, 62, 124, 248 and 496, (the harmonic mean), yields an integer, 5 in this case. … It is the largest happy number less than 500.

## How do you find the perfect number?

In number theory, a perfect number is a positive integer that is equal to the sum of its positive divisors, excluding the number itself. For instance, 6 has divisors 1, 2 and 3 (excluding itself), and 1 + 2 + 3 = 6, so 6 is a perfect number.

## How many amicable numbers are there?

Altogether there are 42 pairs of amicable numbers below 106.

## Are 60 and 84 Amicable numbers?

Amicable Numbers The Greeks considered the pair of numbers 220 and 284 to be amicable or friendly numbers because the sum of the proper divisors of one of the numbers is the other number. a. 60 and 84 are amicable numbers.

## What does the number 28 symbolize?

The number 28 symbolizes balance, harmony, service to others, empathy, adaptability, divine life purpose and soul mission, manifestation of wealth, prosperity and abundance, solving problems, achieving success, knowledge, inner wisdom, the Universal Spiritual Law of Karma, partnerships, authority, finances, leadership, …

## What is the most interesting number?

The number 6174 is a really mysterious number. At first glance, it might not seem so obvious. But as we are about to see, anyone who can subtract can uncover the mystery that makes 6174 so special….Two digits, five digits, six and beyond…DigitsKernel2None3495461745None5 more rows•Mar 1, 2006

## What is a amicable number?

In mathematics: Number theory. …“amicable numbers”: two numbers are amicable if each is equal to the sum of the proper divisors of the other (for example, 220 and 284). Attributing virtues such as friendship and justice to numbers was characteristic of the Pythagoreans at all times.

## Is 1 a proper divisor?

whose only proper divisor is 1 is called a prime number. Equivalently, a prime number is a positive integer that has exactly two positive factors: 1 and itself.

## How are amicable numbers calculated?

Two numbers are said to be amicable if each number is the sum of the proper divisors of the other. A proper divisor of a number is any divisor of the number except the number itself. For example, the proper divisor of 12 are 1, 2, 3, 4, and 6.

## What is the largest perfect number?

for n = 7: 26(27 − 1) = 8128. As of January 2016, 49 Mersenne primes are known, and therefore 49 even perfect numbers (the largest of which is 274207280 × (274207281 − 1) with 44,677,235 digits)….Hours of Instruction.SunClosedFri3:00 PM – 7:30 PMSat9:00 AM – 11:00 AM By Appointment Only4 more rows•Feb 17, 2016

## IS 220 a perfect number?

Perfect numbers have the property that the integer divisors sum to the number. … The factors of 220 are 1, 2, 4, 5, 10, 11, 20, 22, 44, 55, and 110, which sum to 284.