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. In scientific notation this is 1051, and the full number spans 52 digits. Sexdecillion is the 16th term in the short-scale "-illion" series — the system used in the United States and modern British English. The prefix sex- means six, combined with dec- for ten, giving the 16th position (sex + dec = sixteen). In the long-scale system used in parts of continental Europe, the same word refers to 1096, or 1 followed by 96 zeros — nearly double the exponent. See also: Zeros in a quadrillion.
A sexdecillion has
51
zeros
- Written Form
- 1 followed by 51 zeros
- Scientific
- 10⁵¹
What Is a Sexdecillion and How Many Zeros Does It Have?
A sexdecillion is a formally defined integer equal to 1051 — the digit 1 followed by exactly 51 zeros. It is not an informal term. The zero count comes directly from the short-scale formula: the nth "-illion" has 3n + 3 zeros, so for the 16th "-illion": 3 × 16 + 3 = 51.
To write it out without scientific notation requires 52 digits in total: See also: How many zeros in a sextillion.
1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000
Sexdecillion sits between quindecillion (1048) and septendecillion (1054) in the sequence. 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.
How Many Zeros in 100 Sexdecillion?
One hundred sexdecillion equals 1053, which has 53 zeros. Each factor of 10 added to a sexdecillion increments the exponent — and the zero count — by one:
- 1 sexdecillion = 1051 — 51 zeros
- 10 sexdecillion = 1052 — 52 zeros
- 100 sexdecillion = 1053 — 53 zeros
- 1,000 sexdecillion = 1054 — 54 zeros (= one septendecillion)
This scaling behaviour is identical across all "-illion" names. Whether you are 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 in the sequence.