How Many Zeros in a Sexdecillion?
By Vinitha Published Updated
How many zeros in a sexdecillion? A sexdecillion has 51 zeros: 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, or 1051 in scientific notation. It is the 16th term in the short-scale "-illion" series used in the United States and modern British English. To see 10¹⁵ in scientific notation and long-scale naming differences, read quadrillion zeros.
A sexdecillion has
51
zeros
- Written Form
- 1 followed by 51 zeros
- Scientific
- 10⁵¹
The Sex- Prefix and Sexdecillion's Position
The direct answer: exactly 51 zeros. The prefix sex- means six, combined with dec- for ten, giving the 16th position (sex + dec = sixteen). The zero count follows the standard formula: the nth "-illion" has 3n + 3 zeros, so 3 × 16 + 3 = 51. Questions about writing 100 in scientific notation are answered in how many zeros in a hundred.
Sexdecillion's Position in the Sequence
- Comes after
- Quindecillion —
1048 - Comes before
- Septendecillion —
1054
The step from one named number to the next always adds three zeros in the short scale, so knowing the zero count for any one name makes the surrounding ones trivial to derive.
Sexdecillion vs Its Neighbors
| Name | Zeros | Scientific notation |
|---|---|---|
| Quindecillion | 48 | 1048 |
| Sexdecillion | 51 | 1051 |
| Septendecillion | 54 | 1054 |
How Many Zeros in 100 Sexdecillion?
- 1 sexdecillion =
1051— 51 zeros - 100 sexdecillion =
1053— 53 zeros - 1,000 sexdecillion =
1054— 54 zeros (= one septendecillion)
Whether you're working with a billion or a sexdecillion, multiplying by 10 always adds one zero, and multiplying by 1,000 always advances you to the next named number. For more on the digit 1 followed by 66 zeros, see how many zeros does an unvigintillion have.
Watch: How Many Zeros in a Sexdecillion?
How many zeros in a sexdecillion? A sexdecillion has 51 zeros — 1 followed by 51 zeros. Watch this short video for the zero count, the written form and the notation at a glance.
Zeros in a Sexdecillion: FAQ
What comes before a sexdecillion?
Quick answer
Hundred quindecillion comes right before a sexdecillion.
What comes after a sexdecillion?
Quick answer
Ten sexdecillion comes next, followed by hundred sexdecillion and then septendecillion.
How many digits does a sexdecillion have?
A sexdecillion has 52 digits in total — that's the digit 1 followed by 51 zeros.
How many zeros in 2 sexdecillion? In half a sexdecillion?
Two sexdecillion keeps the same 51 zeros. Half a sexdecillion has 50 trailing zeros after the 5.
Is a 51-digit number always a sexdecillion?
No. A 51-digit number tops out at hundreds of quindecillions — a sexdecillion is the first 52-digit number.
How many zeros in a sexdecillion in the British system?
Under the old long-scale system, a sexdecillion meant 1096 — nearly double today's short-scale value.
About the Author
Designer and Developer · Palakkad, Kerala, India
Vinitha holds a bachelor's degree in Textile and Apparel Design from Avinashilingam University, plus a C-Tech certificate in Graphic Design from Image Creative Education. She builds free, no-clutter reference tools like How Many Zeros. Read her full bio.