| 2147483647 | |
|---|---|
| Cardinal | two billion one hundred forty-seven million four hundred eighty-three thousand six hundred forty-seven |
| Ordinal | 2147483647th (two billion one hundred forty-seven million four hundred eighty-three thousand six hundred forty-seventh) |
| Greek numeral | ͵γχμζ´ |
| Roman numeral | MMCXLVMMCDLXXXMMMDCXLVII, or MMCXLVIICDLXXXMMMDCXLVII |
| Binary | 11111111111111111111111111111112 |
| Ternary | 121121222121102021013 |
| Quaternary | 13333333333333334 |
| Quinary | 133442234340425 |
| Senary | 5530320055316 |
| Octal | 177777777778 |
| Duodecimal | 4BB2308A712 |
| Hexadecimal | 7FFFFFFF16 |
| Vigesimal | 1DB1F92720 |
| Base 36 | ZIK0ZJ36 |
2,147,483,647 or 2147483647 is a Mersenne prime. It is the result of 231−1, and it is one of only four known double Mersenne primes. 2,147,483,647 was the largest known prime number until 1867. It is also the largest possible unsigned 32 bit integer.

At the time of its discovery, 2,147,483,647 was the largest known prime number. In 1811, Peter Barlow wrote:
Euler ascertained that 231 − 1 = 2147483647 is a prime number; and this is the greatest at present known to be such, and, consequently, the last of the above perfect numbers [i.e., 230(231 − 1)], which depends upon this, is the greatest perfect number known at present, and probably the greatest that ever will be discovered; for as they are merely curious, without being useful, it is not likely that any person will attempt to find one beyond it.
He repeated this prediction in his work from 1814, A New Mathematical and Philosophical Dictionary. Then, in 1867, the number 3,203,431,780,337 was proven to be prime.