3965

3965 is a positive integer. Its prime factorization is 3965 = 5 × 13 × 61, a product of three distinct primes. Because of this, 3965 is square-free and has eight positive divisors: 1, 5, 13, 61, 65, 305, 793, and 3965.

Numerically, 3965 is odd and not divisible by 3 or 9; the sum of its digits is 23, so it is congruent to 5 modulo 9. It lies just below 63 squared (63^2 = 3969), making 3965 equal to 63^2 − 4, i.e., 61 × 65.

All prime factors of 3965 are congruent to 1 modulo 4, so 3965 can be expressed as a sum of two squares in more than one way: 3965 = 46^2 + 43^2 = 53^2 + 34^2.

In Roman numerals, 3965 is represented as MMMCMLXV. As a year, it would be a distant future date in the Gregorian calendar context, with no widely recorded historical events associated with that year.