What is 7 (number)?
{{Infobox number | number = 7 | numeral = [[septenary]] | factorization = [[prime number|prime]] | prime = 4th | divisor = 1, 7 | roman unicode = Ⅶ, ⅶ | greek prefix = [[wikt:hepta-|hepta-]]/[[wikt:hept-|hept-]] | latin prefix = [[wikt:septua-|septua-]] | lang1 = [[Greek numeral]] | lang1 symbol = [[zeta|Z]], ζ | lang2 = [[Amharic language|Amharic]] | lang2 symbol = ፯ | lang3 = [[Arabic language|Arabic]] | lang3 symbol = {{resize|150%|٧,7}} | lang4 = [[Germanic Variant]] | lang4 symbol = <s>7</s> | lang5 = [[Persian language|Persian]] | lang5 symbol = {{resize|150%|٧ - هفت}} | lang6 = [[Urdu]] | lang6 symbol = {{Urdu|7|11|top}} | lang7 = [[Bengali language|Bengali]] | lang7 symbol = {{resize|150%|৭}} | lang8 = [[Chinese numeral]] | lang8 symbol = 七(qi) | lang9 = [[Devanāgarī]] | lang9 symbol = {{resize|150%|७}} (saat) | lang10 = [[Telugu language|Telugu]] | lang10 symbol = {{resize|150%|౭}} | lang11 = [[Tamil language|Tamil]] | lang11 symbol = {{resize|150%|௭}} | lang12 = [[Hebrew (language)|Hebrew]] | lang12 symbol = {{resize|150%|ז}} (Zayin) | lang13 = [[Khmer numerals|Khmer]] | lang13 symbol = ៧ | lang14 = [[Thai numerals|Thai]] | lang14 symbol = ๗ }} [[File:En-us-Seven.ogg|thumb|right|Pronunciation of the number 7]] {{wiktionary|seven}} The [[number]] '''seven''' is a [[natural number]] that comes after [[six]] and before [[eight]]. In [[Roman numerals]], it is '''VII'''. == Mathematics == In [[mathematics]], the number seven is an [[odd number]] and a [[prime number]]. It is also a [[Mersenne prime]]. ===Divisibility Rule=== * To test if an integer is divisible by 7 or not, # Take off the last digit and multiply it by [[2 (number)|2]]. # Subtract that [[product]] from the root number (the integer without the last digit).<ref>[https://www.easycalculation.com/divisibility-rule-by-7.php Divisibility rule by 7]accessed 21 October 2016 </ref> # Repeat the second step again and again until it is clear that the number is divisible by 7 or not. '''Example''' 918785 # 5'''×'''2'''='''10, 91878'''-'''10'''='''9