Numbers 84,000,000s

A page of the Numeropedia - the Special Encyclopedia of Numbers

81,000,00082,000,00083,000,000 – 84,000,000

85,000,00086,000,00087,000,00088,000,00089,000,000

All Numbers  & [1M] & [10M- [20M] - [30M] - [40M] - [50M] - [60M] - [70M] - [80M] - [90M]  &  [100M]

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84,215,045

[Math.]  A regular polygon with this odd number (product of Fermat prime numbers) of sides is constructible by using only straightedge and compass. 84,215,045 = 5×257×65,537.

84,272,400

[Math.]  Sum of the first 135 cube numbers:

13+23+…+1343+1353 = 81,812,025 = (1+2+…+134+135)2 = 91802.

84,521,745

[Math.]  A pair of amicable numbers (84521745, 107908335), one of 5 pairs involving an 8-digit and a 9-digit number.

84,591,405

[Math.]  A pair of amicable numbers (84591405, 89590995).

xy,abc,def

[Math.]  For any xy = 10 to 99, there are always six 6-digit numbers abc,edf such that the sum (xy+abc,def) is equal to one of 6 digit-rotations of 142,857 and the number xy,abc,def is a multiple of 142,857.

For any xy = 10 to 99, there are always twelve 6-digit numbers abc,edf such that the sum (xy+abc,def) is equal to one of 12 digit-rotations of 076,923 or 153,846 and the number xy,abc,def is a multiple of 76,923.