A quadrillion is equal to 1015 in America, or 1024 in France and Germany.

In the long scale, 1015 is called billiard (not to be confused with a game), which is commonly used in France and Germany.

Written out in decimal form quadrillion (in the short scale) is:

1000000000000000

In long scale:

1000000000000000000000000

This number is also called pentillion in Russ Rowlett's Greek-based naming system.

Aarex Tiaokhiao gave the name petillion and Sbiis Saibian gave the names small fry, guppycrumb, and minnowspeck, referring to the short scale value of this number.

Aarex Tiaokhiao also calls this number (in short scale) qndoocol or 15-noogol.

BlankEntity calls this number Jookol.

This number (in short scale) is known as a padma in the Indian counting system.

## Approximations

For short scale:

Notation Lower bound Upper bound
Scientific notation $$1\times10^{15}$$
Arrow notation $$10\uparrow15$$
Steinhaus-Moser Notation 13 14
Copy notation 9 10
Taro's multivariable Ackermann function A(3,46) A(3,47)
Pound-Star Notation #*(2,2,3)*5 #*(2,2,1)*6
BEAF {10,15}
Bashicu matrix system (0)(0) (0)(0)
Hyperfactorial array notation 17! 18!
Fast-growing hierarchy $$f_2(44)$$ $$f_2(45)$$
Hardy hierarchy $$H_{\omega^2}(44)$$ $$H_{\omega^2}(45)$$
Slow-growing hierarchy $$g_{\omega^{\omega+5}}(10)$$

For long scale:

Notation Lower bound Upper bound
Scientific notation $$1\times10^{24}$$
Arrow notation $$10\uparrow24$$
Chained arrow notation $$10\rightarrow24$$
Steinhaus-Moser Notation 18 19
Copy notation 9 1
Taro's multivariable Ackermann function A(3,76) A(3,77)
Pound-Star Notation #*(1,2,3,3)*5 #*(2,2,3,3)*5
BEAF {10,24}
Hyper-E notation E24
Bashicu matrix system (0)(0)(0)
Hyperfactorial array notation 24! 25!
Bird's array notation {10,24}
Fast-growing hierarchy $$f_2(73)$$ $$f_2(74)$$
Hardy hierarchy $$H_{\omega^2}(73)$$ $$H_{\omega^2}(74)$$
Slow-growing hierarchy $$g_{\omega^{\omega2+4}}(10)$$

## Examples

• The Niagara Falls use up a quadrillion gallons in a little over 210 years.
• The Great Lakes have a volume of about 6 quadrillion gallons.
• It is about 586 quadrillion miles from one end of the Milky Way to the other.
• The SI prefix peta- multiplies by one quadrillion.
• 1,000,000,000,000,000 to 10,000,000,000,000,000 (1015 to 1016) – The estimated total number of ants on Earth alive at any one time (their biomass is approximately equal to the total biomass of the human race).
• 9,007,199,254,740,992 (253) – number until which all integer values can exactly be represented in IEEE double precision floating-point format.
• 48,988,659,276,962,496 is the fifth taxicab number.
• In Isaac Asimov's Galactic Empire, in what we call 22,500 CE there are 25,000,000 different inhabited planets in the Galactic Empire, all inhabited by humans in Asimov's "human galaxy" scenario, each with an average population of 2,000,000,000, thus yielding a total Galactic Empire population of approximately 50,000,000,000,000,000.
• There are 7.205759×1016 different possible keys in the obsolete 56-bit DES symmetric cipher.