3966

3966 is a natural number that follows 3965 and precedes 3967. In decimal notation, it is an even and composite number with several notable arithmetic properties.

Its prime factorization is 3966 = 2 × 3 × 661, where 2, 3 and 661 are prime. Consequently, 3966 is square-free and has eight positive divisors: 1, 2, 3, 6, 661, 1322, 1983, and 3966. The sum of its divisors is sigma(3966) = (1+2)(1+3)(1+661) = 3 × 4 × 662 = 7944. The digit sum in base 10 is 3+9+6+6 = 24, so 3966 is divisible by 3 but not by 9.

In various numeral systems, 3966 is represented as follows: in binary it is 111101111110, and in hexadecimal it is 0xF7E. In Roman numerals it is written as MMMCMLXVI.

As a year label, 3966 could refer to a year in any calendar system that uses that numbering, though there is no widely recognized historical event tied to this exact year in common-use sources. In mathematical contexts, 3966 is often cited as an example of a product of three distinct primes, illustrating properties of divisors, factorization, and base representations.