Natural number
75 (seventy-five) is thenatural number following74 and preceding76.
75 is aself number because there is no integer that added up to its own digits adds up to 75.[1] It is the sum of the first fivepentagonal numbers, and therefore apentagonal pyramidal number, as well as anonagonal number.[2][3]
It is also the fourthordered Bell number, and aKeith number, because it recurs in aFibonacci-like sequence started from itsbase 10 digits:7,5,12,17,29,46, 75...[4]
75 is the count of the number ofweak orderings on a set of four items.[5]
Excluding theinfinite sets, there are 75uniform polyhedra in the third dimension, which incorporatestar polyhedra as well. Inclusive of 7 families ofprisms andantiprisms, there are also 75uniform compound polyhedra.
|
|---|
|
|
|
400 to 999 |
|---|
| 400s, 500s, and 600s | 700s, 800s, and 900s | | |
|
|
1000s and 10,000s |
|---|
| 1000s | |
|---|
| 10,000s | |
|---|
|
100,000s to 10,000,000,000,000s |
|---|
- 100,000
- 1,000,000
- 10,000,000
- 100,000,000
- 1,000,000,000
- 10,000,000,000
- 100,000,000,000
- 1,000,000,000,000
- 10,000,000,000,000
|
|
|