... fully, plus the 19th digit partially [-2 63 -1 to 2 63- 1] ~ [9,2 23, 372, 036 ,854,775,808 to 9,2 23, 372, 036 ,854,775,807]. Practically this data type is safe to compute most of standard arithmetic ... Fac(n) = n * Fac(n-1). Example: Fac (3) = 3 * Fac(2) Fac (3) = 3 * 2 * Fac(1) Fac (3) = 3 * 2 * 1 * Fac(0) Fac (3) = 3 * 2 * 1 * 1 Fac (3) = 6 Iterative version of factorial long FacIter(int n) ... 95 93, 326,215,4 43, 944,152,681,699, 238 ,856,266,700,490,715,968,264 ,38 1,621,468,592,9 63, 895,217,599,9 93, 229,915,608,941,4 63, 976,156,518,286,2 53, 697,920,827,2 23, 758,251,185,210,916,864,000,000,000,000,000,000,000,000...