691was the MAA (Mathematical Association of America) number of the day on 19 February 2013.MathBabbler Number Analyst (MBNA) output: ========================================= 691 is a natural, whole, integer 691 is odd 691 proper divisors are: 1, 691 is deficient (sum of divisors is 1) 691 is unhappy 691 is a Squarefree Number 691 is not a Harshad number 691 is prime ...Truman Gerald prime with 661 ...OEIS:002145 (4n+3; n=164) 691 is the sum of 13 consecutive primes 691 = 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 691 in octal is 01263 691 in hexadecimal is 0x2b3 691 in binary is 1010110011 (is evil) 691 nearest square numbers: -15...38 (676...729 [27]) sqrt(691) = 26.2869 ln(691) = 6.53814 log(691) = 2.83948 691 reciprocal is .00144717800289435600578871201157 691! is 6.32012e+1663 691 is 219.952 Pi years 691 is 34 score and 11 years 691 written as a Roman numeral is DCXCI 691 = 346^2 - 345^2 and 346 + 345 = 691The MAA reported that

`is the "only prime number that is a square when turned upside down (169) and another square when reversed (196).`

691The MBNA reported that

`is the sum of 13 consecutive primes and the MAA reported that it is the "smallest prime that can be written as the sum of thirteen consecutive primes."`

691

Creator:Gerald Thurman [gthurman@gmail.com]

Created:19 February 2013

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