Isaac Scientific Publishing

Journal of Advances in Applied Mathematics

Number of Digits in Two Integers and Their Multiplication

Download PDF (252.4 KB) PP. 69 - 74 Pub. Date: April 1, 2019

DOI: 10.22606/jaam.2019.42004


  • Xingbo WANG
    Department of Mechatronic Engineering, Foshan University, Foshan, China Guangdong Engineering Center of Information Security for Intelligent Manufacturing System, Foshan, China State Key Laboratory of Mathematical Engineering and Advanced Computing, Wuxi, China


This paper first proves a formula that discloses the relationship between the number of digits in multiplication and its two divisors, then proves that the two divisors are of the equal length if the divisor-ratio generated from the bigger divisor divided by the small one is smaller than 10. Hence the paper shows that, all the RSA numbers must have two divisors of the equal length.


Number of digits, multiplication, divisor, RSA number.


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