The Hitchhiker's number is equal to \(2^{276,709} \approx 5.11764 \times 10^{83,297}\).[1] It was coined in The Hitchhiker's Guide to the Galaxy, a comedy science fiction novel by Douglas Adams. Adams jokingly gave this number as the reciprocal of the probability that a spaceship would pick someone up in the cosmos during a period of 30 seconds.
The number contains exactly \(83,298\) digits, placing it just under a googolgong, and larger than \(6 \uparrow\uparrow 3\). This makes it small enough to compute and store the full decimal expansion on modern computers.
Decimal expansion
Its full decimal expansion is in the link below:
Hitchhiker's number/Decimal expansion
Properties
It is the largest googolism which is a power of 2 with an exponent coprime to 6.
The prime factorization of 276,709 is 17 × 41 × 397.
Approximations
| Notation | Lower bound | Upper bound |
|---|---|---|
| Scientific notation | \(5.117\times10^{83\,297}\) | \(5.118\times10^{83\,297}\) |
| Arrow notation | \(2\uparrow276\,709\) | |
| Steinhaus-Moser Notation | 5[3][3] | 6[3][3] |
| Copy notation | 7[7[5]] | 8[8[5]] |
| Taro's multivariable Ackermann function | A(3,276706) | A(3,276707) |
| Pound-Star Notation | #*((95))*135 | #*((96))*135 |
| BEAF | {2,276709} | |
| Hyper-E notation | E[2]276,709 | |
| Bashicu matrix system | (0)(1)[3] | (0)(1)[4] |
| Hyperfactorial array notation | (7!)! | (8!)! |
| Fast-growing hierarchy | \(f_2(f_2(14))\) | \(f_2(f_2(15))\) |
| Hardy hierarchy | \(H_{\omega^22}(14)\) | \(H_{\omega^22}(15)\) |
| Slow-growing hierarchy | \(g_{\omega^{\omega^4+\omega^214+\omega3+9}2}(16)\) | |
