50
It is 4060.
A little over 100, although mathematicians disagree over it's exact value.
40 Factorial = 815,915,283,247,897,734,345,611,269,596,115,894,272,000,000,000
100!This was the original answer, which I left because it's funny. While the answer is 100, 100! represents one hundred factorial, a far, far greater number.
There are 24 trailing zeros in 100 factorial.
1.0309
100*99*...*2*1= 93326215443944152681699238856266700490715968264381621468592963895217 59999322991560894146397615651828625369792082722375825118521091686400 0000000000000000000000
50
99!, which, according to another contributor to WA, is 93326215443944152681699238856266700490715968264381621468592963895217 59999322991560894146397615651828625369792082722375825118521091686400 00000000000000000000
The value of 9 factorial plus 6 factorial is 363,600
It is 4060.
The question, as asked, is difficult to answer, The number of zeros in factorial 100 is not the same as the number of 0s at the end of factorial 100 since there will be some before the end.The answer to the second question is easy:The number of zeros is determined by the number of 10s in the factors.Since 2s are common, this, in turn, depends on the number of 5s.In 100!, there are 20 multiples of 5 each of which will contribute a 5 to the factors of 100!.In addition there are 4 multiples of 52 = 25 each of which will contribute another 5 to the factors of 100!All in all, therefore, there are 24 5s giving 24 0s at the end of 100!
factorial of -1
A little over 100, although mathematicians disagree over it's exact value.
26 factorial is 403,291,461,126,605,635,584,000,000
18 factorial is 6,402,373,705,728,000.