TL;DR: One trillion is 10¹², so one trillion to the tenth power is 10¹²⁰ — a 1 followed by 120 zeros, which is a 121-digit number. Written out, it begins 1,000,000,000,000,000,000,000,000,000… and continues for another hundred digits. It has no everyday name; it is far larger than a googol’s square root and far smaller than a googol.
The rule that makes it easy
A power of ten raised to a power multiplies the exponents.
So (10¹²)¹⁰ = 10¹²⁰. That single step does all the work, and the rest is writing the zeros out.
This is why scientific notation exists. The number is impossible to read in full — not because the value is difficult, but because the representation is unreadable at that length. In exponent form it is four characters.
Three related examples that use the same rule:
- (10³)⁴ = 10¹² — a million squared pattern, one trillion
- (10⁶)³ = 10¹⁸ — a million cubed, one quintillion
- (10¹²)² = 10²⁴ — a trillion squared
Each is a multiplication of exponents, not of the numbers themselves. Squaring a trillion is not “a trillion times a trillion” in any way you would want to compute by hand; it is an exponent addition.
How many digits, and how to count them
The number of digits is the exponent plus one. 10¹²⁰ has 121 digits: one leading 1 and 120 zeros.
That relationship is worth remembering because it converts an exponent into something concrete. An exponent of 120 does not feel like a size; “121 digits” does, and it is immediately comparable to other numbers.
For the same reason, the digit count is the standard way to compare very large numbers. Comparing 10¹²⁰ with 10¹⁰⁰ is trivial — 20 more digits — while comparing the written-out forms would be hopeless.
As a physical intuition, writing 121 digits at one digit per centimetre would span about 1.2 metres. It is a number you could write across a table, which is a reminder that exponent size and physical size are unrelated.
How big is that, really
Comparisons are the only way to make a number this size meaningful, and honest ones are scarce.
Versus a googol. A googol is 10¹⁰⁰. One trillion to the tenth is 10¹²⁰, so it is a hundred billion billion times larger — or 10²⁰ times larger. It is not “close to a googol”; it is twenty orders of magnitude beyond it.
Versus the observable universe. Estimates put the number of atoms in the observable universe around 10⁸⁰. So 10¹²⁰ is about 10⁴⁰ times larger than that atom count — a trillion trillion trillion trillion times more.
Versus real counting. Count one number per second and 10¹²⁰ seconds is around 10¹¹² years. The universe is roughly 1.4 × 10¹⁰ years old, so the counting time exceeds the age of the universe by more than a hundred orders of magnitude.
The pattern in all three comparisons is that the gap is expressed as a subtraction of exponents. That is the only arithmetic that stays tractable at this scale, and it is why nobody tries to reason about these numbers any other way.
Why this specific number gets asked
Two reasons, and both are worth knowing because they explain the traffic rather than the mathematics.
It appears in a viral audio clip, where a voice asks what one trillion to the tenth power is and the answer is sung or shouted as a string of digits. The clip spread because the answer is absurdly long, and people search for it afterwards to check whether it is a real number or a joke.
It also functions as a benchmark in casual “biggest number” arguments, in the same family as a googol and a googolplex. Those arguments usually conflate notation with size — a googolplex is 10 raised to a googol, which is a number whose exponent is itself vast, and it dwarfs 10¹²⁰ completely.
An important clarification for that family of comparisons: 10¹²⁰ can be written down; a googolplex cannot, because writing it would require more digits than there are atoms in the universe. The distinction between “very large” and “not writable” is the interesting one.
Reading and writing such numbers correctly
Three conventions that prevent errors.
Count zeros in groups of three. Writing 120 zeros by hand invites a miscount, and a miscount by one zero changes the value by a factor of ten. Group them as 40 groups of three.
Use the exponent in any working. Convert to exponent form before doing any arithmetic, then convert back if a written form is needed. Multiplying the written forms is where mistakes appear.
Know where the names stop. The short-scale naming system has names up to about 10³⁰⁰ in theory, but most of them are never used outside reference tables. 10¹²⁰ has no name anyone would recognise, and inventing one invites confusion.
For checking an exponent expansion or converting between forms, a power of two and exponent calculator shows the value and the digit count side by side, which is the fastest way to verify a number this size without hand-counting zeros.
The short version
One trillion is 10¹², so the tenth power is 10¹²⁰ — 121 digits, 1 followed by 120 zeros. Multiply exponents rather than numbers. It is 10²⁰ times a googol and 10⁴⁰ times the estimated atoms in the observable universe, and it is entirely writable, unlike a googolplex.
