Skip to content
EntityQ44535· pop 35· linked from 324 articles

happy number

Sign in to save

Also known as happy numbers

numbers with a certain property involving recursive summation

Wikidata facts

Show 1 more fact
maintained by WikiProject
WikiProject Mathematics
Sources (1)

via Wikidata · CC0

~13 min read

Encyclopedic overview

Tree showing all happy numbers up to 100, and 130 Sad numbers up to 100 showing the repeating cycle of 8 numbers In number theory, a happy number is a number which eventually reaches 1 when the number is replaced by the sum of the square of each digit. For instance, 13 is a happy number because

1

Excerpted from Wikipedia’s “happy number” article, available under the CC BY-SA 4.0 licence.