What is a happy number?
Happy number. A happy number is defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits in base-ten, and repeat the process until the number either equals 1 (where it will stay), or it loops endlessly in a cycle that does not include 1.
In number theory, a perfect number is a positive integer that is equal to the sum of its proper positive divisors, that is, the sum of its positive divisors excluding the number itself (also known as its aliquot sum).
- 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.
- In recreational number theory, a narcissistic number (also known as a pluperfect digital invariant (PPDI), an Armstrong number (after Michael F. Armstrong) or a plus perfect number) is a number that is the sum of its own digits each raised to the power of the number of digits.
- The usual ordinal form is "twelfth" but "dozenth" or "duodecimal" (from the Latin word) is also used in some contexts, particularly base-12 numeration. Similarly, a group of twelve things is usually a "dozen" but may also be referred to as a "duodecad".
Adam Number. Adam number is a number when reversed, the square of the number and the square of the reversed number should be numbers which are reverse of each other. Adam numbers upto 1000 are: 0, 1, 2, 3, 11, 12, 13, 21, 22, 31, 101, 102, 103, 111, 112 , 113, 121, 122, 201, 202, 211, 212, 221, 301, 311.
- Adam number is a number when reversed, the square of the number and the square of the reversed number should be numbers which are reverse of each other. Adam numbers upto 1000 are: 0, 1, 2, 3, 11, 12, 13, 21, 22, 31, 101, 102, 103, 111, 112 , 113, 121, 122, 201, 202, 211, 212, 221, 301, 311.
- The area codes or prefixes 800, 833, 844, 855, 866, 877 and 888 are used by toll free numbers in the United States, Canada and all the countries covered by the North American Numbering Plan.
- 2:22: Seek balance. Two is the number of partnership and relationships. When you see 2:22, pay attention to the people who are showing up in your world. You might be bumping into a soulmate, or a soul friend, someone who will play a significant role in your world.
An Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. For example, 371 is an Armstrong number since 3**3 + 7**3 + 1**3 = 371. Write a program to find all Armstrong number in the range of 0 and 999.
- Perfect number, a positive integer that is equal to the sum of its proper divisors. The smallest perfect number is 6, which is the sum of 1, 2, and 3. Other perfect numbers are 28, 496, and 8,128.
- A palindromic number or numeral palindrome is a number that remains the same when its digits are reversed. Like 16461, for example, it is "symmetrical". The term palindromic is derived from palindrome, which refers to a word (such as rotor or racecar) whose spelling is unchanged when its letters are reversed.
- Prime number program in C. Prime number program in C: C program for prime number, this code prints prime numbers using C programming language. C program to check whether a number is prime or not. Prime number logic: a number is prime if it is divisible only by one and itself.
Updated: 3rd October 2019