A digit is a single number.
For example: 0 to 9 are single digits.
The sixth digit of the NAICS code is used to define national industries
25811 is a single (5-digit) number and a single number does not define a sequence.
13227451532 is a single 11-digit number. A single number cannot define a sequence.
29513101917 is a single 11-digit number. A single number cannot define a sequence.
12436871416 is a single 11-digit number. A single number does not define a sequence.
3591733 is a 7-digit number. A single number cannot define a sequence.
133514221125715124 is a single 18-digit number. A single number cannot define a sequence.
03815 is a single 5-digit number. A single number cannot define a sequence.
310172431 is a 9-digit number. A single number cannot define a sequence.
81 is a single 2-digit number. A single number cannot define a sequence.
01246 is a single 5-digit number. A single number cannot define a sequence.
In any measurments the accuratly know digits and the first doubtfull digit are called significant figures